I've spotted a brilliant looking BSA marked spanner on ebay 330855515416 but what is it for and is it really worth the sellers starting bid price? 
That is the strangest spanner I've seen. At about 18" long it's to big to fit in an M20 tool roll 
The ring spanner end is also odd being octagonal, the only thing I can think of that shape is a rifle barrel.
email (option): horror@blueyonder.co.uk
It's really weird isn't it?!!? That's the problem with BSA, they made so much stuff over the years, guns, bicycles, cars and so on, it could be from just about anything. If it was £45 cheaper, I'd buy it just because I haven't got one already. 
Probably too rare (obscure) for its own good...Unless someone actully knows what it is and has the piece of equipment it was made for, it has only nominal value to BSA nutters like me who would have it just out of interest to hang on a nail in the workshop...Ian
email (option): ian@wright52.plus.com
It's obviously a very rare bit of kit, especially if Ian doesn't know what it is! but is it ever going to be worth £50 as a starting bid?
Well it's not worth my £50...
...I'll give him a fiver though..Ian
email (option): ian@wright52.plus.com
Just out of interest, while we are speaking of BSA spanners, I bought one at a car boot sale a while back. It's about 5.75 inches long, one end is for a spark plug and it says SPARK PLUG on it, the middle of the shaft has the BSA piled arms logo and the other end is stepped with a double sized open jaw spanner on it. Anyone know what and from when?