I dunno. Winston was awfully distracted by what was going on in his own front yard. And remember he was out of power till May of 1940. He claimed to be shocked that no defenses had been built on the north end if Singapore. Why didn't he know? Should he have assumed? One wonders. I also suspect that while it may have been militarily correct to give up all of Malaya and Singapore, could Churchill have survived politically if he hadn't put up a fight?