When should I change the timing belt / chain in our Ford S-Max?

We drive a RHD 2009 Ford S-Max that we bought new when we lived in UK. It has now completed 73,500 miles. When should I have the cam belt/chain (not sure which) changed? We really like this car for its fuel economy, long haul comfort (we do about five trips back to UK a year) and most importantly, load space. What would you recommend as a suitable alternative, with an equitable load carrying capacity to ferry two teenagers' stuff for school and university, and of course similar fuel economy.
If it has a diesel engine, then it is due for a timing belt replacement. If it has a petrol engine, that is chain cam and all it needs is clean oil. Nothing has actually come along to replace the S-Max in terms of ride, handling and 7-seater capability. It remains the only 7-seater sportscar, and we will see a new S-Max at the Frankfurt Motor Show in September.
Answered by Honest John on

Ask Honest John