....But I must say, that from Nordic perspective any discussion of a cold start in UK sounds a bit amusing.
I know what you mean, having been in the industry doing engine calibrations for potentially arctic markets (Canada etc). We had to guarantee an unassisted start after a 12hr soak at -35C with a 70% battery. It's quite normal for some form of protection or assistance to be used in conditions below this.
What I mean by a cold start doesn't really refer to the ambient temperature as such, it's really meaning starting the engine after it has not been run for a prolonged period, overnight etc. This will be when the calibrations will be for an "ambient" start rather than having any residual warmth in the engine oil and coolant etc.
If the engine has run within the last few hours then things will be different.
Whatever the conditions, fuelling can often be different from the normal during cranking and for a number of seconds or revolutions after the engine sustains running, I always like to give it time for these fuelling strategies to ramp off before driving, but as said earlier this is typically only 20 or 30sec. We used to do plug foul tests which consisted of blipping the throttle repeatedly during this cold afterstart period, that's the way to get plug fouling if it's going to happen, soft carbon and water condensation together will foul plugs.