Bit of an update...
You could have knocked me down with the proverbial feather when I went to our local vintage-tractor-and-vehicle rally - and found this sitting there:
This is a '55, petrol, and stayed in the Army until 1986. The owner seemed very knowledgeable about them, and what they could do. For example, and with reference to dad's photos (I went home to fetch them), the Scammells normally 'hunted' in pairs - one could winch out a bogged Centurion tank on its own, but it was easier and quicker in a battle situation, with two. He said that there were 2 crew to each recovery vehicle (he didn't seem to like the term 'wrecker'), and both men had the same training, so either could drive if one was wounded.
Interestingly, it was his opinion that the 'smash-ups' had been damaged by shellfire, and not just road accidents as I had thought; so they had been recovered from battle situations. We will never know; although I can see what he means, there isn't much frontal damage on any of them?
I must admit I felt a bit of a lump in my throat, when I opened the driver's door of this Scammell, and saw a vision of my dad sitting there among all the bare metal and man-size levers.
Oh and I'll post some more photos from that day, there were a selection of Fords from Majors to a couple of TW15's, maybe make a new thread for Shows etc?