It looks like a very nicely built machine, even with the brown tape marks on. Cleaning that should be no trouble for anyone buying the machine, and I definitely think it is well worth £2000+, especially if you also can demonstrate it working, which you say you can. I do agree that it may be easier to sell for an even better price if it would be completed, but even as it is since it is actually a working machine, not just parts and promises, you should have no problems if you find the right interest group. Try here as well:

http://www.cnczone.com/forums/

There is more life on that forum even if it is a USA based one. There are probably other forums as well.

I am sorry you have to give it up when you are so near the finishing line, and wish you good luck with the sales.