Hi, and a happy new year.

Zafira b 2011 what's the temperature the cooling fan comes on?

Happy new year to you too Shiny !

Thermostats usually open around 80 degree centigrade but cooling fans rarely come on until around 100 degrees when the engine is hot due to idling when stationary without airflow.

If you have Air Conditioning then the A/C fan would fire up occasionally to bring the interior temperature down

I am using the secret settings/BC button to get a temperature on screen as the B has know temperature dial on the dash(silly).

I have just changed the radiator and temperature gets in the nineties before a slight drop (no fan) thermostat must open, cold weather stopping the fan kicking in after around 10 minutes ticking over?

Well I guess if it is not overheating and the heater is blowing warm then as long as the coolant level doesn't drop then it should be fine.
There may still be some air in the system but that will always work its way up to the expansion tank eventually.

Coolant level is fine, just driven 50 miles all ok, I can see the level through the new expansion tank I fitted as the old one was very dirty.

Edited 10 hours ago10 hr by Shiny