The email states "we already have this on our data base as a confirmed Sandman" so I would say the seller Mark originally emailed or messaged Byron requesting info.

Personally I don't see anything wrong with the advertisement.... It is a Sandman, the seller is up front and has the original 6cyl engine and there are plenty of pics of the van, he also received info from this site confirming it as a genuine HJ Sandman and has conveyed that in his listing.

i do think it is a bit dear for what you get but that is my opinion.... 6cyl is good for a P plater though...