I coach and compete allstar, level 2 or 3, depends on whether it's all girl or co-ed. Do regional and national competitions mainly - BCA, Future Cheer, Jamfest, ICC etc. Did go to the internationals a few years ago but that was when I was competing more than coaching. Going to Blackpool Empress Ballroom this weekend for another regional than that's it for 2011!
I don't think we're really that bad for allstar teams in this country, the UK cheerleading scene is never going to be the same as it is in the US although the standard here has vastly improved. I mean with our level 2 squad we're having to hit tick-tocks braced/with no release and flyaways with no release just to place well (released they would be level 4) and maybe 2/3 years ago that definitely wouldn't have been the case. But anyway loads of people just trophy hunt now instead of levelling up.
Unity Black, Ascension Eagles, Aviators just to name a few are all of a very, very high standard at open level and compete at Worlds. I agree the UK probably isn't going to field junior 5 teams anytime soon but things are certainly going in the right direction. It's difficult with University squads though because you have your atheletes for maximum 3-4 years and it's hard to get everyone at the same standard unless you have requirements for your competition teams.
Tumbling has never come naturally to me either, I think some peoples BHS look so effortless and graceful, I'm just too slow in the air! I am disgustingly flexible though, I don't really fly, especially not on all-girl I'm too tall but I can still hit bow and arrow and needle which I'm pretty pleased with!