This post will get shouted down.
B&W speakers are known to be bright (no bass) and if partnered with a bright amp just sound horrible... Rumor has it that Rotel amps favour/are tuned to suit B&W speakers...I don't know if that's true or not but I've seen it written often enough to think there is some truth in it.
I was as a die-hard B&W fan (still am with subs) but when I upgraded awhile back and ended up with a Cyrus system through all the listening in hi-fi shops, I came to realise that B&W speakers are not all they are cracked up to be. Good yes but there are a lot better speakers out there than their 600 and 700 series. Several folk have said change the speakers. I would endorse that, try something else and you might never look back... I haven't.