Hey Deacon,
Since I'm in the states I dont know a ton about shops in UK/Europe... But, I have come across these sites and figured I'd throw the links at you:
http://www.chainreactioncycles.comThey arent really a flatland specific shop it seems but they do carry a bunch of parts that cross into the flatland world...such as the Mac tires/tyres Daddycool was talking about... I think they're in Ireland but they seem to ship everywhere.
https://www.kunstform.org/en/Much more flatland parts/bmx centric... Gonna guess and say they're in Germany.
Tire preference is a pretty rider specific choice... I haven't tried the KHE ones yet. Right now I'm riding the "expensive" Ares ones...well, not the kevlar ones. so the slightly less expensive ones
. I love them myself. I love them more when the center is mostly bald and the edges have the tread left. I was riding the Odyssey Frequency G's before. But, just a couple days ago I threw on a new pair of those I had laying around and came home and instantly put my bald Ares back on. The Frequency Gs felt so slow compared to the Ares (I pumped them up the same as I do the Ares. Ares can stand a bit more pressure than the Odysseys but i dont go that far...100-110psi). It could be too that the Frequency's were brand new and just needed some brake in time. For what it's worth though, before I switched to the Ares I loved the Odyssey's. If I had never tried the Ares I'd probably still be riding those.
It's good to have you in the global-flat community man. You get some topics going in a rather quiet forum
!
cheers