The A6r is an evolution of the A6, and therefore is similar sounding in most ways, which is pretty much how most of the Spendor A Series sounds. The D7's are quite a contrast. We always felt that the A Series was a little too smooth for our liking, but they obviously suit many people as the range is still around and sells. But the D7's are far more lively and detailed - if anyone was listening to these and didn't know what they were, I doubt anyone would guess they are a Spendor design. Great sounding speakers which deserve to do very well for them.
Other than being bery popular, the £2-4k speaker market is quite a strong one at the moment, with hardly a duff design no matter which way you turn.