OK, so I've pretty much got it down to a shortlist of one.
Having looked at Behringer (cheap, but not flexible enough), Samson (quite expensive for what you get, and not a brilliant rep), Yamaha (built like a tank, but you pay for it), and Peavey (used one before - it was always OK, but never anything special, and really heavy), I've pretty much decided on the Phonic Powerpod 1860 Plus.
It's got the Aux sends, onboard FX, plenty of power (measured at sensible levels of distortion too, none of this peak power lark!), 8 mic inputs, and the amp stage can be switched between Main L/R, Mono Main/Aux 1, Aux 1/Aux 2 and Bridged Mono. And it's under £400 [url="http://www.stagebeat.co.uk/P/8559/POWERPOD+1860+PLUS+POWERED+MIXER"]here[/url].
Anyone had any experience of this fella? I've used Phonic stuff before and it's always sounded OK, if not outstanding, and has been pretty reliable in the past - anyone had any bad experience with them?
Andy