I also have a Fiat Ducato and when it requires servicing i know how many hours etc is required to do the job so does Skoda have this. My new dealer to me is saying it will take all day to do 4 year service, any comments .

All service departments will have manufacturer-specified times for each particular job on the car. These are the hours you get billed for. They may want to keep the car all day, but they won't be working on it all day. Most garages like you to leave the car with them so they can fit jobs around the working day and maximise their technicians' time.

4 year service will include cambelt change. So yes, I'd expect it to be more than half a day, with time spare for any issues and if you approve, getting the work done.

A normal service is around 60-90 min for a minor, and 2-3 for a major.