Thanks for that Ace,
Unfortunately, to keep the ship, it must be in a condition that complies with the WNT, which means the armour must go. Yes the engines are kept as is. Despite having fought a war, as per normal the battleships spent less time at sea than most, which meant their machinery did not get the same hammering as the BC's and below. I am happy with using the removed boiler space for extra fuel and stores, young trainees always seem to eat more than the more mature sailors. Using the removed boiler space for extra fuel is done in WW2 to extend the range of destroyers converted to long range escorts.
Would filling the double bottom with bits of removed armour and turret do instead?
My original thought was to use the 4 turrets removed from each ship to arm the BC Sud Afrika (and a sister) in the other thread. But since I got a bit of flak in using refurbished turrets for new ships I redesigned the 14" to a 12" for that ship type.
Overall the RN would be aware of the changes made and would have exact amounts as to what was necessary to be replaced and where any ballast might need to go. So I have no problem in your queries, questions, and solutions put forward, as it keeps me thinking about 'balance' when I am hacking bits off ships to create my monsters.