2. the compressor & hence the system operating at freezing temperatures
What will this prove? I've no idea if my compressor operates at freezing temperatures (I simply assume it doesn't) as I've never gone to the trouble of looking, but I do know that if it does operate it is unable to produce the same conditioned air it can in normal circumstances.
The point is that if its -1c outside, the air conditioning being on or off will make no difference to your demist. It isn't providing the assistance it normally does for demist purposes, which the owners manual of the car backs up.
So I guess we have a choice - do we beleive you, or all the owners manuals of all the cars in the UK and a qualified automotive engineer who works on HVAC systems...
TOUGH CHOICE