Blobeye squeeling drive belt

[Shaqs77]

Hi guys

on start up I’m getting the dreaded squeeling sound before it dies away after a few minutes. I have taken up the tension but after a few months starting again. I’m guessing because it’s slipping, it’s not charging the Battery sufficiently and hence getting starting issue. 

 

I want to replace the belt but don’t know which one to get. Euro car parts have a 50% sale but it’s coming up with several variants. Can anyone here point me in the right direction please.