Where a surviving Repulse might have served

Would the Royal Navy have returned a surviving Repulse to action without a major refit?

Probably after a limited AA upgrade, pairing her with Renown and carriers in a fast Eastern Fleet group.

The Royal Navy would still need modern fast capital ships after losing Hood, Barham, Prince of Wales, and Ark Royal. The proposed response pairs Repulse with Renown after a short refit, then uses the two battlecruisers with armored carriers as a mobile Indian Ocean force. Repulse would likely receive at least an anti-aircraft upgrade before returning rather than undergo a long reconstruction. The resulting fast group offers an alternative to relying on slower battleships in the Eastern Fleet.