Allis Chalmers HD-7s

[Micetro]

It's my first post here so hello to you all! 

I've been looking into the history of the Allis Chalmers tracklayers in Army/Engineer's service during WWII with the HD-7 in particular drawing my attention. My interest in Allis in particular is in-part because my Grandad had wheeled Allis tractors on the farm and while I was too young to remember them the family album always sparked something. 

Looking at some of the Landing Tables for Neptune it seems that a number of them were employed during the Invasion, is this actually the case or have I got the wrong end of the stick please? 

Also would they have been used by the Engineers who were building airfields and Advanced Landing Grounds both on the Continent and back in Blighty? 

Finally, does anybody know of any survivors in the UK/Europe please? as I can only find reference to one HD-7, an HD-10 which was in a grader setup and another HD-10 which was fitted with a blade and was purported to have taken part in the Invasion of France. 

Attached is a pic of what I understand to be a REME HD-7 with a Garwood angle-blade although I stand to be corrected! 😀 

Cheers, Tom