just as the 5th Indian and 6th and 9th Australian Divisions were also released from Middle East Command.
When is the 6th Australian due to arrive? Also what is the status of the 1st Australian Armoured Division and in particular its 1st Armoured Brigade?
He could then send 17th Indian Infantry Division to Persia where it could continue its training
That seems very very plausible. After all, in OTL after the end of the invasion of Iran, the 17th brigade was detached from the division and was sent to Egypt. Moreover, the soviet counter-offensive in Moscow starts in a couple of days. Even those that believe the USSR will collapse would think that such event will take place during the next campaign season at best. So there is more than enough time for the 17th Indian to get trained in Iran, waiting for a possible soviet defeat.
Combining the OTL events and the timing at the Eastern Front, it seems that such exchange of formations will be very easy to pull.
With the end in sight in Libya, Wavell would still have more than enough forces
And Wavell is not going through attrition due to a continuous air campaign. The RAF Middle East command can send a trickle of aircraft after the Japanese attack, over the winter.
Now that I think of, having schedule the movement of 4 divisions (5th Indian, 6th & 9h Aus, 11th African) since autumn 1941, there is significant lift capacity at theater level. Is it fair to assume that the British have the capacity to move another two divisions from Egypt to SE Asia by February ?