Every Caviar House location has a different price and they change all the time, based on supply and demand. Often not what you would expect. Last time I flew LHR-HKG the LHR price was about 30% cheaper than the HKG price -- I expected the opposite, but given the emergence of affluence in China and the decline of UK perhaps it isn't a surprise. Quality was identical (I tried some at both locations on the same trip).

Ducasse pricing is completely separate, and generally lower (if USD 100 for a small side of salmon can be called lower).