I don't normally do gaming appraisals, but hey. This is a very brandable domain in a high revenue sector, and therefore I would advise waiting until you receive an offer that reflects this. I note that ipoker .co.uk is currently on DomainLore and is currently at £850 from 2 bids and will probably go higher. x is probably not quite as strong as i, but the ipoker sale will give you an idea of potential.
Also, if you check on domainprices.co.uk you'll see some other strong poker sales going through.
Rgds