
As TimG pointed out that particular fuze was used in a Naval shell and would have Fuze 243 marked with a naval N.
I would point out that you cannot use a shell having no squeeze capability with a littlejohn adapter.
I would also note that I said 2Pr Mks 9A and 9B when I should have said Mks 9A and 10A guns.
I was only making a point that the fuze was not purely used in naval service.
Usually, there would be no need to bar out a naval N, all you do is place a contract for the identical fuze for land service use and marry that with a shell having a Design Drawing Land (DD(L)) Number. If you were making a cartridge for use with a naval shell, the fuze contract would call for a naval N marked fuze and would go into a shell having a Naval Ordnance Drawing (NOD) number.
There were occasions during WWII when naval shell were diverted for use with land service cartridges to meet a short fall for special events, such as the Normandy landings, provided the RN did not have a greater need. All weapons and ammunition for all three services plus outside customers , came under one umbrella, namely the Directorate of Inspectorate of Armaments (D.I. Arm) (as was) and whose requirements for what, would be thrashed out at meetings and contracts placed accordingly.
The drawings at the top are both for a Shell 2Pr HE/T Mk 2 identical in every way, except one has a NOD Number and the other a DD(L) Number. This would have been a case in point.
I would doubt that the immediate needs could not be met from the various existing lines of supply. Provided the fuzes at that time were still unfilled but marked N, this could be barred out, but once filled it would not be prudent to do so.