my 2006 FZ6N has 43,300 miles on now. most of the time I'm riding with 1000cc sports bikes, so to say it gets a bit of stick would be an under estimation, It gets an oil and filter change every year or 5,000 miles, chain lubed every week, bike cleaned with insect remover and WD40 to get chain lube off the a polish with Mr Sheen.
Changed the coolant, fork oil and brake fluid last winter and put new spark plugs and air filter in, greased swing arm and rear shock.
I would think it's worth £1500 ish but mileage puts people off, if it was a car it would have very low miles? bikes that are stood for years without being used I would stay away from.
Most cars do 100,000 miles + so why not bikes.