Would you rebuild Glorious and Courageous before the war to improve their endurance and usefulness?
Short answerYes, with a full single flight deck and better deck-edge arrangements, if the money and time lost from service could be accepted.
NotesA thorough rebuild would remove the forward round-down, extend the flight deck over the bow, and reorganize the weapons in a style closer to later British carriers. Glorious and Courageous could become more useful carriers, but the work would consume money, dockyard time, and operational availability. Modernization remained a force-planning choice with a real cost.