I agree 'but' what would Adm Tom Phillips have done post this late evening surface engagement?
Knowing that surprise was lost and that he was badly out numbered - would he not return to Singers and await reinforcments which he knew were days away from arriving?
OTL, that's exactly what he did - turned for home at 2015 on the grounds that surprise was lost, received a report at 2335 of a second set of landings around Kuantan, and judged he was far enough from Japanese air bases and in an unexpected position so that surprise would be achieved.
TTL, per Matt Wiser's comments, Kurita will attempt to draw the British north-east, a game Philips is unlikely to play. A brief surface engagement will ensue, with each side attempting to disengage and fall back on support without being trailed. Given the disparity of force, this is probably going to end in two or three Japanese ships sunk, though any hits on REPULSE will tell given her light armour.
After their disengagement, the British ships will be known to be heading south, probably with some damage. A return to Singapore does seem probable under those circumstances, with Kurita falling back on the Japanese battleships. By the morning, they're still in range of Japanese air attack - the TENEDOS was detached from the force at 1835, about an hour before the tentative surface engagement, and was attacked by a flight that got separated from the main force.
With the ships damaged and retreating southwards after the surface action, I think it's likely that the signal requesting air cover is sent more quickly. OTL, the TENEDOS was attacked at about 0950, the main force was being shadowed from 1020, and the air attack began shortly after 1100. Fighter support wasn't requested until 1158, with aircraft showing up at 1315. TTL, with the ships expecting action, assume the signal is sent immediately the attack begins, shaving an hour off, and the closer proximity to Singapore reduces flight time by about half an hour; this is consistent with being 100 to 150 miles closer.
Assuming the air attack is as OTL, that puts the fighters on the scene just after the first torpedo attack. This was the wave that hit PRINCE OF WALES's shaft, pretty much the definition of a Golden BB. The total of two torpedo hits is likely to remain, but with less damage. Subsequent waves will be disrupted by fighters, and probably ineffective, especially if PRINCE OF WALES and her AA battery remain in action. The Buffalo was a particularly rubbish fighter, but the G3M and G4M were particularly vulnerable bombers, and it doesn't take much to throw off the aim of torpedo bombers. Losses amongst the Japanese bombers will be correspondingly higher, though there's only so much a few fighters can do.
End result is PRINCE OF WALES torpedoed twice and possible damage to REPULSE from 8-inch shellfire, in exchange for two or three Japanese cruisers sunk and significant losses amongst the attacking bombers. PRINCE OF WALES will need dry docking - probably an emergency patch job at Singapore before heading to Trincomalee. She'll probably return to Europe after repairs, joining the vigil against Tirpitz. This frees up an American fast battleship for the Pacific, which may be useful in the Solomon Islands. REPULSE, if not too badly damaged, will be repaired at Singapore. She'll probably be refitted with much more AA armament and return to the Indian Ocean as a fast carrier escort.
The Japanese losses will weaken them at Sunda Strait (though not Java Sea), but it's unlikely that makes much difference. They will also be weaker for the Indian Ocean Raid, during the course of which the 7th Cruiser Division was quite effective against British merchant shipping. After that, my crystal ball gets hazy.