Hi Roger,
I have no idea what the official response from Miele will be, but I suspect that if the Revolution models have indeed been dropped from the UK line-up, it's to push people towards purchasing from the S7 range. Whereas in the past, they tried to blur the boundaries between uprights and powernozzle canisters (remember their tagline 'Thinking of an upright? Think again!'), now they have a dedicated upright line, they don't need to do this anymore.
From what I've heard from a very credible source from within the industry, Miele are really having trouble selling the S7 at the moment - too heavy and too expensive. I guess right now it needs all the help it can get! Perhaps when (or IF!) sales pick up, we'll see the Revolution models re-introduced. I agree with you that they can't ever have been big-sellers.