golf arrived a week ago with mil illuminated read code p000a/000010 camshaft a bank 1 intake slow response code .engine very low on oil so topped up with correct grade and cleared codes .vehicle ran ok and returned to owner .returned 1 week later for service and reread fault code.code returned,. oil and filter changed and flushed .suspected timing chain tensioner problem so stripped out cover and found hydraulic tensioner pushed out to max (30mm)and chain still slack.my query is do these engines have known issues with timing chains and what parts should be replaced out of course ie cam adjuster ,oil pump,as well as chain and tensioner .the head has to be removed as cyl leakage test points to valve to piston contact any advise gratefully received