How about the brand spanking new Prestige Cuvée from G.H. Mumm, the 1998 Mumm Cuvée R. Lalou which is exactly £100 from Selfridges and the Real Wine Company? This is a new departure for Mumm and 1998 is its first ever vintage (and their equivalent of Moet's Dom Perignon, Bollinger's RD &c), produced only in the tiniest of quantities from the finest of parcels. A blend of 50% Chardonnay and 50% Pinot Noir, aged for 9 months in new oak it has notes of honey, orange and nougat, with a crisp, clean finish.