Thanks for the responses guys,
I have sent him two invoices, the duration in which to pay is five days. I dion't really know what posessed me to sell something on eBay anyway, it seems like a lot of messing about. I'm a bit pissed off because the guy is getting something half the price that it even sells in game shops for half the price, and they still can't be bothered paying promptly. I use eBay to buy most of my motorbike stuff and I always pay instantly. The other thing is I don't want to get bad feedback from the guy.