Dom,
I have read many books on the subject, it appears that for several reasons, partially broken codes as well as seeing the Singapore, Dutch East Indies invasion fleets heading south. Everyone knew something was going to happen in the next few days.
Most expected the Japanese to take on fairly weak British/Dutch forces to obtain oil/raw materials. What they did not know, was that the Japanese Carriers were heading to Pearl.
They had given several War warnings to the Philippines and Hawaii Commands, yet both were essentally caught napping. Kimmel and Short (Hawiian Navy/Army) were canned, MacAurthur (Philippines) should have been!
As far as the Coventry attack goes, to say the Brits "helped" the Germans attack Coventry is way over stating what happened.
Through partial reading of the German codes, Churchill knew that Coventry was to be bombed. He was forced to made a Terrible decision.
Send the RAF fighters to Coventry, evacuate the city......both would alert the Germans and loose the incredably valuable code advantage or keep quiet and let Coventry be destroyed.
It was a horrable "Sophies Choice", in retrospect, I and most historians feel he did the right thing.