Hi. My son has a 2017 MK8 Ford Fiesta 1.1 Zetec 3 cylinders (Engine code XYJB) Does this have a wet belt which causes loads of issues? Any help gratefully welcomed. 

Yes, it has wetbelts.

Though so far we haven't seen any break on this engine.  That may be because of differences in the way the turbo engine works.  Or it may simply be because there were very few non turbo-versions built compared to the number of EcoBoost versions.

Yes, as Tom mentions, I don't recall an instance of failure being reported on here (cross everything!😀)

It may be because the non-turbo with its lower power/torque puts less stress on the belts, or because it has port, rather than direct, fuel injection the possibility of fuel dilution of the oil is reduced. 

Or perhaps owners are more diligent with servicing? - in any event, annual oil/filter changes are a good idea.

Or, simply because there are so few around, as already said.

NB that the belt is due to be changed at 10 years maximum as a normal service action, many consider it prudent to bring that forward a couple of years.

Ford have recently revised their policy on out of warranty support for premature wet belt failure (see below). We are not sure if/how this applies to the non-turbo version but it may be worth noting.