Well I have done it and replaced the core of the system with a Meridian 557 power amp. The result is lovely, lots of detail and great refinement and control. Can't wait for the 565 surround pre-amp to arrive.

it also looks great, and my wife commented, ooh that's a big one.
My plan is to get Meridian centre and rear speakers, active or DSP, and to keep the fronts as the Dali Ikon 6 mk'2's which work well with the 557. Currently the other channels are via good Pioneer a/v amp to Mission satelites with Mission sub.
I am using Chord Epic speaker cables, if anyone else has tried other cables with a 557 and Ikon's or similar nuetral Floorstanders I would be interested to hear about it.
A big thank you to Richard who sold me the amp, and Chris J of M Repair for his advice and help.