Question about brickwork and fitting new exterior doors? Help!

[linspins]

We're having a new back door in a wall, and have had a surveyor calculate the lintel needed and the builder cut a neat new hole in the brick work, for the door company to fit in to.
Is there anything that has to be done to the hole, before the door is fitted? I vaguely remember one builder who quoted for us muttering about thermal breaks or something about insulation...its above the damp proof course, so that is ok, but worried we are missing something and the door company will turn up and not be able to fit because we haven't capped the brickwork or some such thing!
( the house has cavity walls )

you should look at fitting cavity closures to seal off the gap , these are basically some sort of insulation that stop the draughts, your new door will sit alongside the outside bricks and will prob not be wide enough to bridge the gap so internally will just be plaster board which has rubbish thermal properties - www.google.co.uk/search?q=cavity+closers&biw=1366&bih=673&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjJ5qerk7rNAhWhD8AKHQFCDikQ_AUIBygC&dpr=1#imgrc=Qmn1V95VhPbsnM%3A

Beaufontboy, you are a star, I think those are the things that were mentioned!
We've super insulated the rest of the house, it would be silly not to do this.
Thanks you. Anything else I am missing?