Ouch. See regulations under "Chalice, Poisoned, Receipt of". At least the people on the ground are working out just what sort of bear-trap they're being asked to stick their hands in. But Britain must, politically, be seen to be Doing Something so a bunch of poor sods are still going to get the opportunity to win posthumous VCs.
Regarding future plans, I'll note that if an invasion of Rhodes is not considered practical in the near-term, then an invasion of Sicily is not likely to be practical any time in the foreseeable future.
Regarding the Far East, the Japanese attack on Malaya (unlike the German attack on Greece) was not some overwhelming assault with massive materiel superiority and succeeded largely due to the poor training, equipment and organisation of the third-string units opposing it. In the short term, a viable armoured force, even if it's just a couple of battalions of older tanks, has the potential to to significantly affect the campaign (consider that many of the Japanese mobile forces were relying on bicycles, and their tanks made the Italians look good).
But in the wider picture I'm with
@GrahamB - the only way Malaya/the East Indies are going to get significant reinforcements above and beyond OTL is if the British get credible warning in advance or if they've already wrapped up operations in Africa, Greece and the Aegean (and Syria/Iraq if those go off) to the point where they have units sitting around in Egypt doing nothing. Otherwise the active front will take priority and Singapore will get whatever/whoever is considered not fit to face the Axis but "good enough for Malaya".