Thanks for answering guys.
The FT4 reckons I burned 1314 calories durning 1hour 46mins of biking my local loop. My riding buddy said that was probably 25% more than it should be.
User info is correct as far as I can see:
Weight 80kg, Height 178cm, birth date 04/01/1961, Sex Male,Max Heart Rate 185. I set this last value after noticing my heart rate was 185 after I’d sprinted up a particularly steep bit of un-paved road as fast as I could.
I think the FT4 is a cheapo model and as far as I know it doesn’t have a fitness test on it.