We have mostly energy-saving fluorescents, but one light is on a dimmer switch. Despite the link above, I have been unable to find anywhere which stocks dimmable fluorescents, what they recommend are halogen filament bulbs. These are less energy-efficient, although they use about 25% less power than old-fashioned bulbs, and are C-rated.

The catch is that EU regulations won't allow frosted glass bulbs unless they're A-rated, so these are all in clear glass, which throws horrible shadows. Presumably the idea is to discourage us from using these bulbs in the hope that we'll have our dimmable switches rewired and use fluorescents instead. Instead, I've stocked up on old-fashioned filament bulbs.