Great pictures there, mate!.
In the second picture, is that SE cable running into the top of that panel?.
In the third picture, is that a timber slat, in behind that ceiling fitting?
This looks like it isn't going to be an easy job, by anybody's stretch of the imagination.
As an EC, I used to do a lot
of fire jobs, the washing machine wasn't all that keen on all the soot in my overalls either.
That's why I'd quote as high as humanly possible, the less of them jobs the better.
Anyhow Marc, fire or no fire, it looks like it was time to re-wire anyway!.
Best of luck with this one.
Oh and by the way, some "After" shots would be cool!