You should have the B47 engine fitted to your car (which replaced the notorious N47 which had all the problems with the chain). We would check to see what engine you have fitted as if you have the N47 then we would be looking to replace the chain at 80,000 miles. If however you have the B47 engine and the engine is serviced correctly (i.e oils/filters) then in theory there should be no reason to have the tensioner checked etc. If you were to actually inspect and adjust the chain you might as well replace it. If however you can hear any signs of rattling coming from the engine then we would replace the chain sooner rather than later.