Morris Minor Owners Club

I spun off the old oil filter yesterday and rather pleasantly, I did without the need for a strap or screwdriver punched through the case.

The part is branded "Masterparts MOF.25" but I've not found anything remotely close to it so perhaps this firm went out of business already? There is a South African firm with the same name but they're a parts distributor.

I've found "GKN Masterparts" who use (or have used) "MOF" designations but the close match I've found from them is "MOF 25 X". "GKN Automotive" are a firm based in Brum who might be the ones but who today only deal in drive and propshafts, steering racks and coil springs.

Doing a simple task of finding an oil filter is taking me way longer than it should so here I am, asking kindly for advice please.

If you "spun off" the old oil filter, your car has probably been fitted with a conversion kit at some stage as Minor 1000s had paper elements originally, fitted inside a metal cylinder. Most (if not all) conversions use the canister oil filter from slightly later Minis which are very readily available from Morris Minor and Mini specialists. Most large car parts/accessory outlets and motor factors will also have parts books to cross reference part numbers.
You should have very little difficulty obtaining the correct filter.

https://www.ebay.co.uk/itm/184697855855 ... BMtsGt_Olg

https://www.morrisminorspares.com/engin ... 1a-p830096

Thank you!

I suppose all conversions use the same oil filter type then.

No - They are not all the same.
The mounting threads can be different, the seals can be different, the size of the filter can be different, and some incorporate a non-drain seal inside the filter body.