Had the clio in cause of the brakes failing, and told them about the knocking.
Had a phone call today and have been told it needs a complete new exhust system. Which theyve ordered.
I spoke to the engineer who looked at the car and he told me that this has been the problem with the mk1s regarding knocking and theyve fixed a couple like this. The mk2s have a single cat pipe and the mk1 have a dual, which was modified on the mk2s due to the knocking problem.
The new exhust will be a modified dual cat piped version, which will hopefully stop the problem. Fingers crossed.