Timing Belt interval is 5 years or something like 120k, but they key detail is "whichever comes first" as these things degrade over time and arguably a car with low miles over 5 years will have had more wear than an engine with 120k motorway miles over 5 years (lots of stop start, heat cycles, unloaded reving causing belt stretch).
I would get it replaced at 5 years regardless of mileage to be on the safe side, however it isn't cheap - expect to pay 520 ish including waterpump, which you should do as if it leaks after the belt as been changed you'll have to pay for a whole new timing belt set up again to get it replaced..
I have my car serviced on the 10k cycle, which sometimes is less than a year - however there are a fair few short journeys in that time and these are the journey's where the engine is running richer than normal and the engine doesn't become hot enough to evaporate water vapor build up in the oil, leading diluted oil, sludge and corrosion over time.
edit to add - take a look at SEAT Fixed price servicing, they are quite competitive and it's a job that carries a danger premium - if it snaps it's likely to need a new engine.