So, after paying the listing fee of £0.27, my running total is now £3.04 (plus a box of 39 spoons)!
I've tried to find out a bit more about the Maltese Cross spoon. It seems that '917' means it contains 917 parts of silver per thousand. So my spoon is definitely silver but not as pure as Sterling which contains 925 parts per 1000.
I've taken a couple of photos so if anyone can give me an idea of age or, even better, value, I'd be very grateful. As I said before, the marks are, from left to right, a Maltese Cross, '917' and 'F'. There is a final mark which is incredibly difficult to work out - it may be of a ship with a square-shaped sail but after staring at it through a magnifying glass for half an hour I came away thinking it could be a big, badly stamped 'H', a rugby goal or a cheese slice...