Raymarine C80 8" MFD / plotter
I have a C80 here in excellent condition having just replaced the screen. 30 day guarantee with this one.
Asking £750 (£625+vat).
These are a couple of generations old now, but still excellent plotters that support the 28XG navionics charts (not included) and unlike the older Raymarine also support AIS display.
This is complete with power lead, choice of trunion or flush mount kit plus NMEA lead for position or AIS input. It will require an antenna if you don't already have something suitable onboard, about £80 on eBay (I can supply).