Found it, are they usually upside down? Is there anything else you can tell from the serial number?
Also, it has this fitted, it appears to be a horn or buzzer of some sort, I've not got a battery to try it out yet.
Before I took it over to Holland for fbi I decided I needed to be able to stop better...
Took it for a test ride and the front fell off
So I welded it back on again