I think you'd have trouble selling the domain.
Is it worth developing yourself? Well, that's for you to decide, but I'd guess there are less problematic fish to fry in your domain portfolio.
I'd take the hit (circa £7) on the chin and next time you go to register a .org.uk, have a look to see what's going on with the .co.uk ... even if it looks generic. Have a look at ipo.gov.uk too - it doesn't take long during their opening hours.
cheers, Luke