I'm in the UK, but dont skate in either London or Scotland. Generally practice sessions in the UK do seem to be called patch. The rinks are quite variable as to the standard of skating required. eg my rink you need LTS level 4, which is pretty basic eg chasses & one foot slaloms. The patches there are still quite empty, and often have high level skaters. I think you would need to check it out with each rink. I suggest you ask on the uk skating forum, if it's allowed I can post the link. If you know where you are staying, it would help. London has several rinks