Right so looking at this I think this is the same head as was found on the standard British rocket just going by the photos.
I know with the UK rockets they switched to a slimmer profile head in later years & one of the changes was non pointed end caps like yours sports.
However as far as I am aware these had "made in England" under the head & didn't have the "II" markings rather they often had an "A" or an "S" stamped under the head.
I used to own two slim profile head rockets with the same style endcaps as yours unfortunately I no longer have them & can't remember whether they had the "II" marking. However I am pretty sure they said made in England.
