The first two are of a gun in British service so it may well be rebarrelled to 7.2 in.
The first two photos are from the Imperial War Museum. (NA 22470 and NA 22472) and are identified as being 155mm Long Tom guns belonging to the 33/61 Heavy Regiment RA at Vergato Italy on 22 Feb. 1945.
Note that the 7.2in Mk VI Howitzer, like the US 8in howitzer, has a shorter, fatter barrel than the 155mm gun.