Have just ordered a Haynes Manual for Fiesta 2002 -2008 so that should tell me if its a belt or a chain.
Good news is that 100k is Ford recomended for change of belt.
As i only do 2000 miles a year , i think i will leave it for a while.
btw it runs ok now i have taken the tyre pressure down to 29 lbs/sq for a load of under three people. The tyres were pressured up to 37 lbs/sq which is for a load of three people or more and it ran like a bag of nails.