Hi golfdave,
This is where I got my information from hence why I did it.
Toothed belt in the valve drive.
In the new generation of engines, Volkswagen was also able to make further significant reductions in internal friction. Take the example of the overhead camshafts (DOHC): the drive here is not by chain, rather by a single-stage, low-friction toothed belt drive with a 20 mm wide belt and load-reducing profiled belt wheels. Actuation of the valve drive via roller cam followers and an anti-friction bearing for the high loads of the first camshaft bearing also lead to reduced friction resistances.
To ensure that the engine takes up as little mounting space as possible, ancillary components such as the water pump, air conditioning compressor and alternator are screwed directly to the engine and the oil sump without additional brackets, and they are driven by a single-track toothed belt with a permanent tension roller.
Volkswagen recommends a five year change interval for the toothed-belt.
http://www.volkswagen.co.uk/technology/petrol/active-cylinder-technology-act
I might be wrong but when I saw this I thought it would be a good idea to change it just in case.