The Nyetimber blanc de blancs 2001 was tasting extremely well last I tried it, and generally any of their wines will spank the pants of off your basic NVs e.g moet or veuve (in particular is awful at the moment). Ridgeview are harder to pin down as they make more wines, but the 05 cavendish is excellent, and some 01 bloomsbury from my cellar had matured really well. Camel Valley I've never really appreciated, Chapel down can be good but I was v dissapointed with their Bacchus' from 07, which is a varietal I normally really like. The new player on the block would be Hush Heath Sparkling Rose which has just picked up a IWSC gold, and is quite serious in a Billecarte Salmon style. So yep, sparkling wines are a genuine concern, both Roederer and Duval Leroy are looking at/buying land over here, as the climate/soil and chalk sub soil are pretty much identical to that found in champagne. Whites from Germanic varietals are less successful, and you can forget about reds, they're mostly a novelty.