Mickey mouse is a technical term used throughout the REME for things that don't seem to fit where they should. Or anything that is a tad puzzling! Like Parker Hale thread systems for instance - and pre No2 revolver Webley now that I come to think about it! Devised by someone on his last day in the office who doesn't give a sh, er...... damn about what follows later.

I'd just make new parts using that other famous mickey mouse thread, the BA system!

Hey, there's nothing wrong with Whitworths BAR. My Norton is full of them!