That's a nice domain and I agree with bensd, just make sure if you do develop it you have a good logo Well done with your catch.
EDIT: Just to add, if you do develop it and are selling logos for low £xxx then I can see the potential value of the site as a whole much higher. If you're just going to sell as is then low-mid £xxx. Maybe get some members here to offer services through it and take a commission on sales?
Considering logos are designed for companies/organisations, the extension doesn't really fit and wouldn't look all that professional in SERPs. But it's still a very nice domain. I would value it at least £500 to an end-user.