When people convert older Minis to rod change, they may need to tweak the new shifter mount a few times.  So they have to insert and remove the pin a few times as well.  MM show the Mini Spares quick release coupler, makes installation easier:

https://www.minimania.com/part/MSG13/Rod-Change-Gear-Selector-Coupling-Quick-Release

Many thanks Scooperman! I tried several MOWOG suppliers but couldn't find the dims. Good price at Mc Master at $14 per hundred, I have an account there so they are now on order. I thought they might be metric, hence the post.

Thanks again, Martin.

Rimmer Bros lists it as 7/32" x 1". https://rimmerbros.com/Item--i-RPS1416?srsltid=AfmBOorWS_nZfmKyDs9TlDli88Jx7IfKAXjbGqFW9sfONlW7A4QzBU3k 

But its a roll pin, more properly named a slotted spring pin, it will expand and won't measure 7/32" when it is removed. McMaster is a good site to check on hardware dimensions, a nominal 7/32" roll pin is designed to squeeze down into a .219" to .224" I.D. hole:

https://www.mcmaster.com/98296A310/

Hi, I'm looking for the dimensions (diameter and length) of the rod change linkage roll pin, part number RPS1416. I can't make out whether it's metric or standard as the ones I have are badly worn. I need to try and source them locally as I need some next week.

Thanks, Martin.