
Obviously for the sake of the puppy, it needs to travel, I think, from the nearest company to where it currently lives? If the breeder is in the habit of sending puppies all over the country, she should know about a good local company.
I have no knowledge of that particular company, but we used a company when moving from the Cambridge area to Devon and as I recall, they were based in the SE. They had them (all adults, one older and 2 litter mates) for 2 nights before bringing them down to us after the move. However, although all 3 arrived safely, I wasn't impressed to find the water bowls in the back of the panel van had slopped all over the place, meaning they were standing, sitting in water, for how long during the journey, I don't know. I'd also say that the one bitch I felt would best cope with all this, was very changed. Previously she'd been fine with people, strangers etc., but after that, she was always reluctant to go to strangers who visited. What, if anything, happened to her while they were away from me, I'll never know (and perhaps I don't want to!)
If you are buying from a breeder in Wales (?!) I think I'd let that breeder make the arrangements. And I think I'd wait until the puppy has had all it's puppy vaccination before having it travel up to you in Scotland.
Incidentally I had a long chat with somebody from the Government doing checks on people who were isolating. We got to talking about puppies/dogs, as you do and I mentioned about getting to a Shelter. He said that should be ok because getting a new dog could be said to be helping with my 'mental health'. So 'essential travel'!!
Finally, do you know these breeders because despite the Corvid 19 lockdown restrictions, it's always best to meet the breeders face to face, and see mum with her puppies, choose your puppy, and note the condition in which they are being reared. There are many BYBs who are cashing in on the fact reputable breeders have stopped their breeding plans at the moment. And charging well over the norm, for their puppies.