your absolutely right, I would personally pay more for .co.uk, purely for obsessive compulsive reasons. but for ranking its easy to rank this long tail keyword with an exact domain, and who actually reads the url anyway? Only competition is a US site - so .org.uk will smash it.
As for selling a domain with 1.2 million exacts cheap, thats not gonna happen. Nice try though!
The department for education has expressed an interest, as a learning resource.
So very unlikely Id sell now, unless someone blew me away with an offer.