Although I am not a Member I felt the need to respond to your situation with your 14 week Border Collie.

You may well have taught him to understand "Come" means to return to you, BUT what your dog does NOT yet understand is that "Come" means to return IMMEDIATELY!

It sounds like your Trainer has not understood the difference from a dog's perspective!!!

Once your dog has learned the "COME" command, you now need to HELP the dog learn to respond immediately.  So do all manner of "Come" exercises in your home, garden and outdoors, when you are in a position to KNOW that he will WANT to come to you, and you can then endorse his recall with "Good boy, Come".  

For instance suddenly sit on your Living Room floor, clap your hands excitedly and call him to "Come" - make a great fuss of him.

In the garden while he is minding his own business, walk passed him and give a quick tap on his shoulder (like a game of tag) and say his name and "Come" then RUN!!  He will chase you, quickly turn round, open your arms beam a great smile and repeat "Come" as he reaches you and love him!

When out for a walk, suddenly say his name with a 'check' on his collar and "Come", then move backwards (make sure there is nothing behind you) lol.  As he is coming in your direction you encourage with "Clever boy COME".

Hope you get the picture.  You will be guiding him and teaching him to understand the MEANING of "Come", and returning to you straight away becomes a 'trained  response' but also an enjoyable one.

All good wishes to you both.

Good advice, but I think Darling buds needs to consider degree, context, and trigger for nervousness first, espesh the submissive urination.
If she already had a nervous pup (poorly socialised by breeder it sounds, or genetically nervous), and now it is unnerved by physical mishandling (smacking the bum, chasing), then your advice may just have the same affect??
Looking at it from the dogs perspective, as you wisely say, and the acts of loudly clapping hands and then giving a big hands on fuss may cause him to submissivley urinate again.
Ditto bending over from on high and tapping his shoulder.
Whilst a lot depends on the manner these acts may be done, I have no doubt a check on the lead would definitely engender a nervous reponse from a young nervous pup, and thus perpetuate this state of mind.
Even a soft check I feel would do this. I would substitute the check with a treat.
LIke I said, Darling Buds knows her own pups limitations, but in my expereince, a pup at 12 weeks that came from a nervous line and is already performing submissive urination would be better of lured and rewarded with high value treats (liver pieces, cheese, etc) in *all* training scenarios.
It is also relevant he is a BC. Along with Shepherds, they are a member of the "reactive breeds", and as the name implies, are way more reactive to everyday sights and sounds, unlike say, a Labrador, who takes them more in his stride.
Hence their use for herding and guarding. BC's can be famously "spooky".   
I would keep the praise positive, cheery, but *relatively* quiet, not as active and enthusiastic and volumnous as is the 'praise reward' training norm. Too much well-meaning noise, body language, and human excitation may spook him too, then risk associating any form of happy human excitement with fear??
I feel the key is for Darling Buds to re-address her own body language.
Keep it natural and flowing, but be subtle, slow, and calm about it. 
New trainer with canine and human body language awareness, plus treat use, is in order, methinks.

I teach all my dogs & my pupils dogs a happy recall from day one, all done off lead in a safe area(back gardens are great), at training classes it is obviously done on lead but with no tugging or pulling.

It is quite simple the dog needs to learn that returning to it's owner is nice & rewarding so titbits/cuddles form an important part. At class the owner steps infront of the dog & steps back calling the dog & making a huge gesture arms outstretched & then brought in front as long as the dog makes the effort to come towards the handler it is praised & given a titbit. As the handler is very close to the dog it has performed the recall, no sit of course at this stage

As the dog gains confidence the distance between the handler & dog is increased & eventually you have the basis of a long distance recall.

At home the training is the same except off lead, this can be reinforced by doing the recalls around mealtimes nothing like an empty tum to encourage a swift return/recall to the handler

All the training is accompanied with lots of praise & a cuddle at the end  of course

Edited to add that I insist that the handlers do not bend over the dog or towards the dog at any time, bending the knees is harder but much less threatening

Sounds like a nice class moonmaiden. All the treat stuff is great and effective.
Would you still recommend the cuddle to a dog that is very nervous and/or reacts nervously to any form of direct human contact and/or is from a nervous breed line?
Or would you systemmatically desensitise the pup to the cuddles first?
Not saying Darling buds pups is nervous of all human handling, incl cuddles, as she hasnt said yet.
(With the info supplied, its a possibilty tho)
Just making a generalised question.

The cuddles are at the end of the training as part of the end of training not done after the dog shows fear etc, using T Touch will desenitize 99.9% of dogs who are nervous & I always have dogs I have used T Touch on coming to me for cuddles & fuss which is very pleasing.

I will quote my my favourite dog training story, I was asked to train a dog to work in "Annie" on stage, the dog was a 5/6 year old X breed who on the outside was very outgoing & confident until he was placed in a new situation when he went to pieces & peed himself in fear as well as running away. I removed him from his owner for training(he fancied the sox off my cavalier so this part was not stressful to him)& in a quiet room with him off lead I gave my already chilled out cavalier(he is chilled out naturally)some T Touch, the dog wandered around & watched me out ot the corner of his eye, as my dog chilled out even more(he ended up on his back snoring ;)) he came to me & actually sat next to me, I very gently touched him with a longish feather behind his ears & on his neck, he was clearly not stressed, I gradually increased the pressure with the feather, until I was able to gently massage him & over a couple of days he was coming to me for the massage all over & would lean into me & he too ended up snoring on his back, During this time I told his owner not to treat him any differently, but asked her to note any change in behaviour.

She was amazed, he was more chilled out at home, more loving & coming for stroking when her other dogs did, he even pushed in for a brusshing which he had never done in the past. Eventually she even tried letting off lead in a safe area with & he was unusually the first back to her. He also stopped pannicking & stressing out if something new or different happened, even greeting new visitors to her home.

When we finished the run of "Annie"in which he stole the show with his performances I showed his owner how to do his massage so she could keep it up & she was surprised that he became so laid back & chilled out & actually asked for his massage by sitting close & leaning in on her something he had never done before. He also stopped his excited barking at doorbells, knocks at the door etc He simply loved being cuddled by everyone in the end instead of being somewhat aloof & withdrawn

He was an ex street dog so no one knows where or what he had come from not what he had experienced, T Touch certainly changed his life

ahhh, of course, Ttouch. sorry, that bit didnt sink in.
that, of course, would greatly override/neutralise touch fear.
seen it in action myself, had it done on me! its amazing.
a real eye-opener; quite literally in the case of the stooge Battersea dog whose wiring had so fused that there were no signs of cognition or recognition for the twenty or so participants whom were around him during the demo.
his eyes were like windows. then, all of a sudden, like an epiphany, he suddenly noticed all these people around him and changed from a reacting machine to an interracting socialite!
this was at a workshop by Sara Fisher. greatly benefitted from those two days, would dearly love to become a practitioner, but, have you seen the price!!

I wouldn't want to be involved on a commerical level & the video & books give enough information & show you how to do the massage correctly !

I have noticed with my belgian sheperd, that in a learning situstion where I need to keep her concentration, she reacts much better to calm praise, than highly excited praise. She is not a nervous dog, soft, but not submissive. She is not an extremely fast learner, but it is now my experience that when I can keep her calm she does learn faster. I use treats and gentle stroking down the side of the head and chest. I would love to learn Ttouch as i am sure both my dogs would benefit from it, can anyone recommend any books?

http://www.ttouchtteam.co.uk/