I'm charging it up now, I think there are a few sheets of paper inside which will let me test it without opening the pack. Because even if the printer is dead (and so far it's looking fine) the pack of paper alone is worth £15 and up on eBay, and the printers sell for £50+
Rather pleased about that one.
Later: it works, but the results are a bit streaky. It turns out that the packet of paper has a use-by date of 2010, the paper in the printer is probably older. Hopefully I will still be able to sell it, but probably not for as much as I initially thought.