Picked this one up yesterday and I was not sure what exactly it is, but following some research I am fairly certain that it is a version of the Satchel Signals No.2, made by Mills Equipment Company (MECo.), it is not dated but has an inspectors mark and number. It has a ZA-13347 stores code which is for signals equipment I think and I found one which had previously sold with all its contents.
Wireless Set 38, Satchel Signals No2 1942, Headphone (08/11/2012)...
Condition is a bit worn and stained but still solid and my Father possibly had one of these during his WWII service.
I tried looking on Karkee web, but they do not appear to cover these.