When I start the car there is a chirpy noise from the engine, sounds like a belt or bearing but goes away when the engine is warmed up.

The thing that puzzles me is the low frequency, only a little quicker than once a second? I'd have thought that the aux belt etc would be moving a lot faster than 60-75rpm even at idle?

According to the service history it has had a recent belt+tensioner change, but according to the same document it also had new spark plugs recently so perhaps take that with a pinch of salt...

To isolate the source try a small splash of water directly onto the outer surface of the aux belt whilst the chirp is present, if no change try for the inner surface. Finally douse the whole belt if you don't notice any change.

 

It's possible at this time of year for a belt to become noisy from road salt, cold temperatures and a glazed surface.