I like the concept, I like the age of the site. It would be interesting to know what you hope to get out of its disposal. What if the UKIP offered you £100 for it but the EU offered you £10,000 to transfer the site to them so they could take it offline?
You're looking more for a buyer motivated by principle than one motivated by profit. And if there's not much profit in the air, it would be difficult to demand a high price. However, get someone like Stuart Wheeler as your buyer and you could make millions!