Mika,
If Heston is your chef of choice then I agree with Aeroman, and recommend lunch at the Fat Duck. If you manage to get in go for the tasting menu, over twenty courses each with a recommended wine! Allow a good three hours and make the most of it.
Tried his new place "dinner" last week and the food was excellent but without the same sense of occasion or theatre.
Both need advanced booking, but you may have a better chance at Dinner. Especially if you stay at the Mandarin Oriental hotel, as the restaurant is inside this hotel. Also may get you some points with Mrs Mika as the hotel is across the road from Harrods.
