Quick update.
After those two idiots were told to get stuffed, one chap got in touch and asked a few questions about the card, asked for more photos, etc. I told him all he wanted to know, sent some pics, he asked what ny lowest price was, I said 75, he said 70 and he came round on Sunday to collect it. Done deal, pretty good. This one was Gumtree.
This afternoon I sold a Thermaltake Berlin 730w PSU which is pretty much brand new. I started the listing at £29 and it sold for £25.91, which I'm content with. except now I get a message asking if I can wait until Tuesday for payment. This was ebay.
It seems that selling stuff depends entirely on what you have, how much your time and peace of mind means to you and your tolerance levels of idiots (of which mine is so bad it's probably a negative number).
I've given him the benefit of the doubt and will wait until Tuesday but I can't see me bothering with this again, too much hassle and frustration for very little money.