I need to move away from N2 for a moment and go back to the bridge, part L2:
Forum member CAG has made a very interesting find! He noticed (in an IWM-held photo of Hood in 1940) that there was some sort of bulkhead or splinter shielding directly under the curved portion of the rear corners of the extended signal platform. EJ Foeth took a look and found the feature on the 1941 photos. I also took a look and confirmed that they are in my photos.
So the detail set will need some extra brass to replicate these shields!
Here is the first image

There is definitely something under the deck!

This is a similar shot...but here we can see that the structure did not reach out to the very edge...

In these photos, you can clearly see the extension (it would be mirrored on the other side of the ship)

This one is very grainy, but it shows the structure very well indeed.

This is what EJ and I think it looked like in plan view.
I also ran this by Maurice Northcott and he was very interested. He noted that there was a mention of bulkwark and shielding being added to the ship in the Spring 1940 update.
Note- you can also see one of the support pillars for the extended signals deck. I'm not sure how many more there were...but it would make sense of they were in each main corner/angle...so we could have anywhere from 2 to 6.