Hi MArk

:
They are GUY QUADS built by Guy Motors LTD Wolverhampton UK
A few of these things ended up here in OZ , I have never seen one with the body intact , they all suffered from the body chop syndrome as civilians had no use for a artillery tractor body.
The gun tractor version production ended in 1943 , but the chassis continued on with a GS body . There was a 4X2 ANT also .
Mike