I have same model and engine and has 69k on the clock. The CVH does make more noise because of the hydraulic tappets while still cold. I guess if the oil pressure and temperature are ok you should not worry. I acquired mine in 2016 and have been driving it for approx 3000 miles per year since and had no issues. Does yours smoke while still cold on idle?
Also has it been unused for a long period before you bought it?
Found this on "https://passionford.com/forum/ford-escort-rs-turbo/378935-how-noisy-is-a-cvh.html"
"Low oil pressure will cause tapping, sticking lifter maybe or a heavily worn cam, also slight piston slap is often misdiagnosed as tapping lifters/cam."
hope this helps;)
