we acquired a collie springer cross 12 months ago he is now 20 months old.  My then partner beleived he could handle the training against my (better) judgement as he had a well behaved older collie already.  Any how, he has now moved out, with his collie and left poor old Diesel (aka Dizzy Dog) with me, collies were not my breed of choice , westies are but thats another story...
So I need advice on training Diesel.   I have read the thread on pulling and will try that, my former other half (FOH) said a halti wouldnt work, but I bought one and do find it better, though we have some kind of zig zag movement going on.  When we go out for a walk as well as the zig zag movement, he barks and yaps all the way to the park, but is fine once at the park off lead.  If I take him out in the car he jumps all around the boot again yapping and barking and makes every effort to push through the dog guard.  If the westie (Dexter) is in the boot with him, he then starts shouting at Diesel so any car journey is a night mare. He also can get aggressive with bigger dogs, particulalry if them come up behind him and he and my friends female husky have taken a real dislike to each other.
I would like to try agility with him but dont know where to start, should I go to a training class, agility or behaviourist first.  In all other ways he is a delightful boy and calming down so much more each day

Thanks in advance
Fiona

I would like to try agility with him but dont know where to start, should I go to a training class, agility or behaviourist first.  In all other ways he is a delightful boy and calming down so much more each day

You've got a very active dog no doubt bred for working (it's a fairly common cross for gundog work). Dogs like that need to exercise their brain as well as their body. I'd say try a good training class (reward based) first, it could make a world of difference. Sounds mainly like a bored teenager that needs to learn some basic manners and have something to do. :)

Re the car I would either tether him to restrict his movement, or better crate him in a crate just big enough (30(L) x 21(W) x 24(H)).  This will reduce his ability to wind himself up with the movement.  Covering the crate woudl also reduce visual stimulus.

On walks as with the puling, when he yaps make like a tree, so that he learns the yapping will stop the progress to the park which he finds exciting.

Teach him 'Watch me' so that he will watch you and shut up, or which he can get a treat.

I would like to try agility with him but dont know where to start

Most agility clubs will require a degree of basic obedience first.  http://agilitynet.co.uk/activepages/clubs.asp?fldName=ClubName  This will give you a list of agility clubs.