Looks like plastic version of old carburetor throttle linkage. 8mm would be close to 5/16 ball. Might try general hardware store assortment bins. Sorry - you are in UK. nevermind............
volvolugnut

Yes indeed, I could have just bought one end but then i'd have needed a longer rod. The end ...

I expect you've resolved this by now but the same happened to me today. Yes it's the plastic inner clip that just crumbles away. I'm not keen on rubber bands to hold it in place as i'll forget, they'll perish and come off again.

The part that i've opted to replace this with is one of these https ...

Well I know the thread is old but still valid info so just to add my pain from the weekend when for the second time I had changed the fuel pump. I did the pump quickly but because it started raining, I rushed trying to get the pipes back on and broke the red plastic clip with the result that fuel ...