Thanks to you guys and your suggestions, I bought a refurb kit for the carb and rebuilt it this morning.
I took the breather assy off the side of the piston chamber and fuel poured out, then took the oil sump plug out and fuel poured out.....so I replaced the gaskets on those, put a new cylinder gasket on for good measure, replaced the valve seat, valve, foam bushes and springs, cleaned out the fuel from the oil sump and engine, put it all back together and.....
Started straight away, runs like a kitten.
Once again, thanks all!