Dynamo identification

[M21]

I have a motorcycle dynamo I am trying to identify, so I can find it a home.

It is about 3"/75mm in diamter, and 7'/175mm long, with an offset shaft. It's almost an exact copy of a "short" Lucas E3, except the the end cover has a diagonal section on it, with two studs marked 16 and 18 for connecting to it. The drive end has a manufacturer's symbol on it, a rectangular box with what looks like half a gear pinion sticking up above it, with a round symbol in the middle, and the letters M 9. Beneath it it is labled P9a.6V.7,5A.

It has a European rather than English feel to it, and I have a vague memory that someone once told me it might be polish. Any thoughts?