I agree with Cyanight about the RAF. Once flown in to kill Italy, they won’t be back on time. However, the UK can base its med-air in Gibraltar without attacking Italy -yet. UK can, just as much as Germany can, hold the options open.
As GE I wouldn’t worry about possible UK blockers in 112 if the UK went agressively into the med. Because after GE1 all the UK has left to block should be 1 destroyer in SZ109 + 1 CA in SZ91. And they are facing (on average) a German BB + sub + the entire luftwaffe. And UK cannot place new ships around GB those first few rounds because of Obvious reasons.
Italy should indeed bomb the British AB to make sure no scrambler can pop out of it. An action with a little risk involved, because the AB has a built-in AAA which has a 1/6 chance to kill the Italian STR. GE moves first so it has to buy its 10TRS and then wait and see if Italy can get the job done. If Italy fails, those 10TRS are almost bought for nothing. Not completely because they can… just for 1 turn… but that’s another story ;-).
Assuming the Brits built the safe 6inf + 1ftr, London has 3 interceptors max (they did Taranto, which is the whole point of buying 10TRS GE2), leaving it only up to the AAA fire of the AB itself. If the UK looses valuable Spitfires versus the Italians in a dogfight, this is even better for GE. Less FTR to fight over London. On top of that, what are the odds of 3 spitfires hitting 3 times @1 (in order to hit the Italian bomber they must score 3 hits). Even with 6 Spitfires this is unlikely enough to even not take it into account…
IMHO Germany (as well as the UK!) should make a calculation every turn: if GE can take London with 15 survivors -meaning all of its Luftwaffe (survivors of the British AAA-fire) plus 5 to 6 ARM- then it is worth attacking for Germany. Surviving the battle for London with less than 15 units will result in the US liberating London US4/5, making it pointless to take… except in those cases where Japan can force the US to spend more in the Pacific, leaving the US less investments for Europe. Germany can take London in such a case with, say 13 or even 11 survivors…
For Germany, having a strong naval defense against the approaching US, preventing it from retaking London is also pointless because this means GE has spent too much IPCs on naval units to also ward off the Russians.