You are on the right track, Mike.
G = Gull Force
SPAR/Sp/S = Sparrow Force
S(ME) is Suez (Middle East) (Not 'Syria'). Ken, I think Aden was penciled in as it was usually by-passed. Ports of call were usually Colombo and/or Bombay (sometimes to the African Coast at Mombasa, Kenya), then Suez direct, but occasionally ships were directed to Aden en-route for some reason, so being an unusual stop, it may be why it was penciled in.
As far as I can tell, the meaning of the dates vary: date of sailing/departure or date of loading (a day or two before the sailing date) and in some cases, the date of release/assignment from store. In several cases, this date pre-dates the sailing date by some days, as vehicles were driven from, say, storage in Melbourne to Sydney for loading onto the ship. Ricks Cove's staff car (AIF M-15 ?) was driven from storage in Melbourne to Sydney for loading aboard the Empress of Japan, for example (can't remember which date shows up in the register for that vehicle, but you get my meaning, I hope).
E = ??
Mike