My sons front mech, a 2011 SLX, has shed the bolt which holds the gear cable in. Does anyone know what type of bolt i need to replace it with…and if its a rare bolt to find on sale alone, anywhere that would stock them?

It’s a stainless steel bolt 8.5/9mm long with M5 metric thread. Take a look at the Shimano Parts Diagram for the part number, then search the internet or ask your LBS to get one in. I find Slanes Cycles are pretty good for Shimano bits & bobs if you can’t find it locally.

Alternative is to just go to your local hardware store and get any stainless steel M5 bolt of about the right length, it’s nothing special. If you’ve lost the plate that grips the cable too, then that is a bit more tricky, and you should get the proper Shimano replacement, though I dare say a washer would make a decent temporary solution!