My order arrived yesterday, I've been too busy to do anything with it until today.
I managed to get around the PAG small order surcharge by placing an order just over the threshold and adding a note saying "Just cancel any items that aren't in stock so that I can receive this tomorrow". I had a day off yesterday so that suited.
I ended up receiving 15 tops - 10 polos and 5 tshirts, and 14 are a good fit. The one that isn't is intended to be a close fit, which doesn't suit me.
I paid £45.33 including delivery, and all of the items seem to be good quality. I won't know until I've washed them a few times, but I'll come back to this thread if there's problems.
Thanks for the recommendation folks!