I agree with Max, Sqwak and Buzz, quite a lot actually. If you do this:
inform IOC/ENG via the Company frequency and are told to close the doors and depart.
then that is asking for trouble. Better to make your own "D".
Also, I was told that
from the moment the aircraft is ready to move for the purpose of taking-off
pertains to the start of the take off roll, not the push. I realise it probably works in the company's favour, but it does make sense that IOC can order you to return to stand (whilst taxiing) if they wish to cancel the flight, for example.