The British had two serious and one moderate strategic naval threats during the 30's; The first was submarine blockade and raiders from Germany, the second is full on open sea fleet action from Japan, the third is Italy cutting off the Med. Germany was never going to be able to build a fleet to challenge the UK, Japan had already done so, and Italy just needed a fleet in being and land based air. To counter Germany they needed Battleships, the old ones will work fine, escort carriers, frigates, destroyers and slack transport capacity. For Japan, they needed Subs, a strong fleet train, strong naval air (full fleet carriers) cruisers and destroyers. Italy, given her position and strategy, needed extra transports (to re route, you can't decisively defeat the Air Force in one action to open the Med, and as long as said air force is there running convoys is really, really risky), cruisers and subs. They were also planning (pretty reasonably) on letting France handle that AoO.