Unless you are sure, beware of sales offers like these. Not suggesting this is the case here, but I was once offered spare wheels for my lorry (at a rally venue); an apparently very good deal, but they offered to deliver them, even though they were not so very local. I only used a mobile phone to tag them along, as I could clearly see them wanting my lorry as a source of further spares!
I've had an e-mail from him. He says he's in Grantham Lincs, and wants £15 each or £12.50 each if the whole lot bought. Thinks they are cedar and has painted them with Cuprinol Shades Green. Personally I think it's too expensive for 2nd hand stuff.