Oil filter ID help

Here's mine.

I think they were originally used on a Citroen Diane or 2CV.

It looks like a copy of the Commando mounting head...which was indeed originally from a couple of French cars.  They were initially quite long filters, but the black, low / short version seems to have become the norm in recent years.

Norton dealers can supply them, the days are gone when the car versions were available in every accessory shop or Halfords.

If you "Google" Commando oil filter alternatives, there are plenty of options.

https://gabma.us/wp-content/uploads/2015/09/norton_filters.pdf

The attached photo shows the RGM Oil Filter Head.

This was fitted to my Commando and came with a very expensive Andover Norton filter.

At the next oil change I purchased a Mahle 0C 5 filter from my local Motor Factor for just £5. 

I have used similar combinations on my 99 and 650 Dominators and not had any issues.

I’m pretty sure they are Citroen 2CV, but be careful if you have clearance issues, some are longer than others - I found the EMGO WW97028 to be the shortest and use them on a a number of my bikes, I get them from a Wassel agent.