If the vehicle has no service history and covered 85K miles or more, it's really not worth having just a new timing chain tensioner fitted, you would be wiser to fit a full timing chain kit and it would be prudent to fit a new balance chain kit at the same time while the timing chain is off.
It is possible that the start up noise is coming from the balance chain and not the timing chain.
You could ring a Vx dealer to check if a previous owner has had any timing chain work done before. 🙂