I have to say that so far I have not yet tasted a lager made in Britain that can approach the quality of the German and Czech produced lager beers.
It's quite amazing how the drinking of quality lager (that is produced under the German Reinheitsgebot laws or their equivalent) has taken off.
I worked at the GBBF from 1991 to 2006, in 1991 "Foreign Beers" was a small subsidiary section tucked way at the rear of Olympia, then the yuppies got a taste for Hoegaarden which is actually a wheat beer brewed in Belgium (I think).
Now "Foreign Beers" is a massive part of the Earls Court set-up, if any of you have a chance to go there ask for Alastair, a genial Jock who runs that part of the show, or at least ran it up to 2006.
My tipple of choice is "Rauschbier" a wheatbeer brewed in Bavaria which has smoked ham hung in it for added flavour, grab it while you can on draught.
If you want decent lager from your local supermarket or offie then I'd say Becks is the best, as I think again it's brewed under regulation, you won't get the "Wifebeater" type hangovers that you get from all the chemically "enhanced" UK and US offerings.
Unfortunately most of the lager available in pubs/bars in this country is utterly foul and gives it a very bad reputation amongst sensible people. You are entirely correct in that some foreign lagers are lovely though.