No worries mate, s1 John is right in the sense that any pro will be able to identify the problem very quickly. But if you like giving things a go...

Not sure where the air temp is on the s1, on the s2 mine is on the cross over pipe. There are three sensor looking plugs for the coolant 1)ECU coolant temp 2)fan switch 3)gauge sensor.

I would also go over all connectors with some contact cleaner and a tooth brush to be certain. Also check the map sensor hose (small black hose going into the ecu).

Im not saying it is defo the sensors, but you don't have much to loose by trying.

If the cold start injector is constantly on this could indicate a problem with its sensor. But this is easy to check by just unplugging.

Does the car start okay, does it run differently when cold/hot?

Rob,