Hi Kieth,
I seem to have opened a can of worms here, please do not be offended by the comments i made about your model.
Here is a little bit opf history of them...
There were 52 required for D-Day as you have rightly said, they were only used by the commonwealth countries, the US flatly refused to use them.
After D-Day these were left on the beaches, as the beacheads were still there and working.
They were operated by the newly formed REME for recovery of beached afv in the shingle, they were also used by the Royal Engineers, for moving obsticles off the beach.
There is also a lot of infomation about these vehicles in the Royal Engineers museam at Chatham Kent ( being an ex Royal Engineer, my old regimental home)
As far as I know, the only working survivor lives in the REME museam in Arborfield, and is owned by Ron, Rex Cadman, of Beltring ilk.
I have been lucky enough to have seen this up close, even helped load and unload this off the wagons, and have been inside, the only thing I wasnt aloud to do is to drive it.
It has been painted/restored to its original colour, complete with all the fixtures and fittings it would have operated with, and is a fantastic site to see, according to the dri ver, fairly awkward to drive as it has no turret and is quite a lot lighter than the sherman TANKS.
Please dont take these comments the wrong way, and remember as has already been mentioned, in planet sherman .... never say never.
cheers,
malc.