From the sound of it, I don't think it's worth more than $500. To be burning oil noticably in 3 years, there is a good chance the engine has been siezed. I bet it would take more than the $2800 difference it would cost to get a new one to get that one into decent shape.
The one thing going for it is that a lot of real OEM parts are still available for the UK version. Use as many of those as you can find to rebuild it and you would end up with a better than new bike.
