Never been to the U.K.
The seed banks I use are located in the U.K.. I do not buy from the local shops because I have had bad experiences with seeds. To be exact 1/10 seeds popped, the problem is they sit on the shelf for long periods of time before people buy them. I know the seed banks in U.K. cycle through seeds at a good rate and give away the old seeds for free. Last time I got a bad batch of seeds from Attitude I wrote a email and they sent me the 10 I bought plus 10 more for free.
Thats why I was looking for a gift card that works in the U.K. Hope this clears up the U.K thing for you.
https://www.cannabis-seeds-bank.co.uk/ AKA attitude seeds