I can get one for USD 50 over here that is refurbished by dell and some as low as 20 by normal sellers. Not sure if it's unbeatable. You also don't give much info about the card. Brand etc?
A quick search tells me that you can buy one for 16 pounds (converted from Euro to pounds ). I'm not sure if it's worth to sell for these prices... I would just keep it in case you ever need it.
You're selling overpriced very old stuff. Not gonna work here, especially on this forum.. Maybe try to lower the cost and post it at your local forum in UK somewhere.
Same goes for that Radeon posted couple of days ago.