I'm due to pick up my diesel yeti in 2 weeks.my question is,does it have a timing belt or chain,and when should it be replaced?

Think you'll find your answers here:

 

 

Gaz

 

Cambelts are every 5 years or 50K miles, whichever comes first.

If you have a chain, I'd suggest a chain tensioner inspection at the same intervals, though I dare say some might say that's not necessary.