Thanks @ChrisSU ChrisSU. This is a really useful summary. The background is that I love my system (15 years old now) but my hand has been forced - the NAC122X got wet and stopped working (is with the service department) - so if that’s not going to be economically sensible to fix then (pursuant your advice) I might upgrade that. To what pre-amp I’m not sure.
If I can get the NAC122X fixed I might take @bruss advice and get a Hicap (a 2?).
The dealer suggested a 250DR and that seemed to come out of the blue rather. Thanks to the feedback here I’m beginning to understand how these things work together and first principles.
I always coveted the next speakers up at the time the B&W 800 series but the general vibe I’m getting is that they’re OK.
I don’t have masses of money.