Thought I'd do a quick update to this to give credit where it's due.
Pics arrived eventually. End cap evidently missing. The marks where he said I'd removed the lamp were made, I think, by the standard packing which I'd replaced before posting but I couldn't explain the pinholes in the board. I can only assume this was down to something happening to it in transit.
Anyhoo, since he wasn't going to refund it, and since he should have paid for the return in the first place due to it being not fit for purpose, I suggested he send it back to me at his expense as a show of good faith and we'd say no more about it. To his credit he's agreed. I'll try and get a refund out of the courier.
I may even try to make it work.