100W×2 Mini Digital Power Amplifier TPA3116D2 2-Channel HiFi Stereo
Bought 2 of these ...one for me and a friends project...friend bailed out so surplus to stock (as with the R Pi3 being offered here) boxed opened, but not used.

here it is
https://www.ebay.co.uk/itm/100W-2-Mi...IAAOSw1-5bDRqY
Cost me £25 and a 40 day wait...you can have it for £18 all in (that includes UK postage only)
No power supply, got a linear one so keeping that.
or you can collect from North London N8