I take it you're not looking to replace your electronics? I think if they're all working fine then you probably don't need to as long as you just want to keep enjoying your music and not diverge into home cinema etc.
There are quite a few speakers to choose from at £1,600 and I would guess that you want to stick to floorstanders? I've heard very few of these, so my opinions are more based on reading around a lot and hearing related speakers.
PMC GB1i - usually regarded as very honest, surprisingly deep-reaching speakers; true to the original recording as you'd expect from a monitor speaker.
Focal 836 - very clear vocal speakers, capable of plenty of bass too.
KEF R700 (slightly above budget)
B&W CM9 (slightly above budget)
Acoustic Energy Radiance 3 (below budget)
XTZ 99.36 (below budget, but sometimes compared to the Monitor Audio GX and sometimes PL range)
You could of course look at standmounts as well, there are some very capable choices around.
Monitor Audio GX100
Dali Mentor 1
To be honest it probably comes down to which brand's sound you prefer, so I'd suggest just going and listening to some alternatives and seeing what best suits your ears. From a purely personal point of view, I'd say listen to PMC and Focal, and definitely read around about the XTZ's.