Don't know if it has already been posted, a search of Jaguar, Adjuster and cog didn't throw up anything..................The headlight adjuster cogs are the same as those used on the Jaguar X type.
There is a full kit to repair x type headlights, in my case the adjusters were fine, but the cogs had gone brittle - luckily you can buy the cogs on their own.
There is also a bodge that can get you out of trouble if your cogs give up the ghost and you need a quick solution - fit a connector block to the end of the adjuster rod where the cog would normally sit
https://www.ebay.co.uk/itm/Rover-75-...53.m1438.l2649