He came out of the trade training school as a Storeman Group C class III. He was then reclassified on 6.1.40 as a Storeman class II (this will have been on the basis of experience in his trade and was not the result of a formal test or examination). There is no indication of the kind of stores he would have been dealing with. In theory it could have been anything which the RAOC handled, which doesn't narrow it down much!
He was admitted to 8 SA Casualty Clearing Station on 9.8.43. It doesn't say when he was discharged. A Casualty Clearing Station is/was a forward Royal Army Medical Corps unit which was the first step in the medical chain. Because he didn't get referred back up the medical chain, whatever he was suffering from can't have been serious. This is likely to have been some illness, not a battlefield injury as PAIFORCE were not in contact with the enemy. I have no idea what "SA" stands for. The war diaries for 8 CCS are in the National Archives and they don't include SA in the unit title.
28/3/44 I can't decipher the word after 'moved from...' but the next bit is Taken On Strength (TOS) M[iddle] E[ast] [Force]. I assume the missing word is a place.
TTQ (trade training qualification) upgraded to ST[oreman] I [class I]. The next line notes that his trade was redesignated Storeman CG (Career Group) class 1.
The last line means that he was posted to 491 Company Royal Army Service Corps. The RASC and the RAOC worked very closely together, as the RASC was responsible for transporting virtually all the stores that the RAOC supplied. This means that he was attached to the RASC company, which in turn would probably have been responsible for re-supplying a brigade. By this time they were fighting in Italy. This may have been because of his specialist knowledge of the type of commodity which the RASC company was responsible for supplying, Petrol, Oils and Lubricants (POL) or heavy ammunition for the Royal Armoured Corps or the Royal Artillery, for example.
Finally you asked about the relationship between 56 (London) Div and PAIFORCE, MEF and BNAF. The Division consisted of a number of units which were grouped together in a fighting formation. The types of unit might vary depending on the sort of military operations being undertaken. The other organisations, such as PAIFORCE, BNAF etc, were largely administrative structures based within a particular location, so PAIFORCE for Persia and Iraq, BNAF for North Africa, and MEF for the Mediterranean area from Gibraltar to Cyprus and including Egypt, Greece and Italy. They handled things like reinforcements, casualty evacuation, shipping, sourcing local supplies and services, in-theatre training, rest and recuperation facilities and so on, leaving the Divisions to get on with tactical matters.
