I have fitted Arnott Gen III's to mine. Had them on now for ten years or so.
The standard pins will fit. I remember running an electric drill bit through the holes to make sure they slide in OK.
Since then I have replaced the pins with stainless steel R clips that I sourced on Ebay. It was a number of years ago however.
There are many suppliers. This is an example of the type I mean:-
https://www.ebay.co.uk/itm/R-Spring-Clips-Retaining-Pin-Shaft-Beta-Stainless-Steel-Hair-Cotter-Pins/283333021341?var=584251117380&hash=item41f7f6ce9dⓂ️mUFnBV5BbojEtPCXXlt_Kvg
You will have to match the size as close as possible. Stainless doesn't rust unlike the original ones.
Addendum: I have got a spare pin in the garage which I can measure if you want.
2000 Range Rover 2.5 DSE HP24 auto, uprated torque converter - JFearn chip, larger intercooler, removable winch, stainless exhaust, alloy radiator, Gen III's, Terrafirma +2" shocks, GG AT2/3's.
Full Fat Faultmate able to do all models.
- ex 1996 Discovery 2.5 300Tdi diesel auto
- ex-1982 Classic 3.86 Perkins diesel manual