I'd flog 'em singly JAmos - maybe if you have some ickle ones, perhaps put a couple together but definitely the larger ones on their own.

I would only buy individual ones myself - mostly because I don't have the pennies to buy a load at once.

Good luck hun - and don't forget to get your buddy to put a photo of the stamps on - also a good idea if you can add a photo of a stamped image so people can see the stamp is in good nick and pop something like a 2p coin next to it so they get an idea of the size of the stamp - a visual is far better than people seeing a size written down and then having to find a ruler to see how big the image is, etc. (add the size in the text too though)

Hugs

C xx