If it’s the one to adjust the shaft length any good diy shop will have something to fit it.
Take it with you show it to the guy in the shop.
Screwfix have everything find a local one. The guys there are very helpful.
From what I remember it’s not a torque wrench. But a grub screw in a collar.
What type of grub screw is it ?
£25 + is a joke.