62 Valiant temperature control cable
Simple is a relative term. In you Valiant it may not be that bad to replace. It's always easy the 2nd time you do it but the first time can be challenging.
I've used cable from a lawnmower and it worked just fine but it's not exactly the correct size so the clamps on the ends may not hold properly. You're best off with the correct cable if you can find one.