Timing belts - quick advice needed

[Tazza]

I'm trying to part ex my 7 It is a standard VVC (built 2000). Part of the reason I am selling is that I have been driving it less and less and it has clocked up just under 7000 miles. The garage I am trying to part-ex say they think that is should have had a timing belt change regardless of the mileage but just because of the age of the car. Is this true or are they trying it on a little?