Rob,
As Mentioned over on HMVF thanks for taking the time to photograph the gun,the pics are of great interest and you can see where the 6 pdr and 25 pdr aspects came into the design of the gun,I think there is a hint of 17 pdr also.
You would think from the design it was possibly going to have some airborne use !
It would be interesting to find some more surviving examples .
Thanks again
Rob......................rnixartillery.