The highlights of the tasting for me were:
Chapel Down Brut Vintage Reserve NV - mostly small bubbles, crisp nose of stainless steel minerality and gooseberries, crisp/acidic/fresh on palate with a nice level of fizz; slightly synthetic aftertaste
Camel Valley 'Cornwall' Brut 2006 - Chardonnay-ish nose and palate, light malolactic, light, non-aggressive bubbles; bit of residual sweetness on the finish
Nyetimber Blanc de Blancs 2001 - mixture of large and small bubbles, very creamy nose, richness on palate - a foody wine

The future of English wine certainly seems to be sparkling. There are some pitfalls which need to be avoided, such as over-chaptalisation (Three Choirs?) and uneven bubbles which fade quickly (Bookers?) Trying to imitate Champagne should also be avoided (Nyetimber - especially their Classic Cuvee?)
The down-side of committing to a future of sparkling wine production is that it is much more capital-intensive than still winemaking. For this reason Stephen Spurrier says he is considering a joint venture with an established champagne house, Duval-Leroy (see article). Maybe this is the way forward for start-up English wineries. Convincing French champagne houses that they need an English producer on their books may well be a difficult task though...