Turns out that Indomitable was never going to make it on time. Even without the grounding she wasn't due to finish working up her airgroup until November 22, which doesn't leave enough time to get from the Carribean to Singapore by December 10.
If the folks in London realize they're not going to have an aircraft carrier available, what's to say that someone might suggest delaying the deployment of Force Z, or at least change the orders.
Have the ships lay over in South Africa a few more days or whatever, and possibly wait for the HMS Hermes to be ready to sail.
That, or perhaps realize that the two battleships themselves aren't going to be enough to stop the Japanese on their own with next to no support forces readily available, and instead of sending them to Singapore, have them stop over in Ceylon or Addu Atoll and use them to start building up the fleet in the Indian Ocean sooner.
They might be of more use as part of a fleet in being than anything else, and given the size of the fleet Britain was able to assemble in early 1942, adding these two ships would actually be a massive force increase.