I have for sale a spin-on oil filter conversion kit that I purchased a year or 2 ago for my 1850 and have not used. It was supplied by Rimmers, part no RB7016 and comes with the original packaging and instructions. It is for those cars without an oil cooler. The kit includes the adapter and fittings but not a spin on filter.
See link: https://rimmerbros.com/Item--i-GRID008243
Rimmers supply these kits at £54.60 plus postage, I would like £25 plus postage please - less than half price! I estimate the second class postage will be around £5 (small parcel) or you can collect from me - I'm located near Swindon.
Any questions please message (PM)