Ok so, I've been doing a little research and digging around to piece the background of some of these images together.
Working down the above photos from the top, we have:
1 - Unknown German truck, but potentially an Opel Blitz judging by the cab shape,
2 - Carro Armato M13/40, Italian Light Tank,
3 - Lee/Grant, couldn't tell you which, I have no idea what the differences were,
4 - "Jerry Petrol Tankers". Looking at what is left of the cabs and engine housing, I think this is actually a Bedford OY tanker?
5 - Your typical Panzer III,
6 - Monty's Old Faithful as established above,
7 - I honestly don't think there's enough of these vehicles visible to identify them, but I'm more than happy for someone to prove me wrong,
8 - This is an interesting one, a vehicle I never even knew existed... It's apparently a 15 cm sFH 13/1 (Sf) auf Geschützwagen Lorraine Schlepper(f). Basically an SPG on the captured French chassis of a Lorraine 37L Carrier. I think they might have been used exclusively in Africa as sources say Rommel requested them and only around 55 were made.
9 - "Captured Tank". Another Lee/Grant, however from what I've found it is now extremely likely that it was captured by the Germans and they retaken by allied forces at a later date.
10 - Lots of Bedford trucks and a Crusdaer(? correct me if that's wrong),
11 - As mentioned above this is a "Rogers Trailer" with a Grant/Lee on, and last but by no means least,
12 - Another Bedford.
The confusing thing about some of these pictures at first was that they claimed to be of captured vehicles that I'm now sure are actually allied vehicles. However, most of these were taken near the Port city of Mersa Matruh (Marsa Matruh nowadays I believe). So, I think... After the battle of Mersa Matruh in June 1942 (a disaster for the Allies, following an even worse disaster at Gazala earlier that month which lead to the appointment of Montgomery), the Axis forces acquired lots of Allied equipment and fuel that was left behind by a fleeing X and XIII Corps. So the convoy of German Tankers (Allied vehicles) and the "captured" (retaken) tanks back up the idea that my Grandad was in this location AFTER the Battle of Mersa Matruh in June 1942, and no earlier than November '42 when these areas were swiftly retaken by forces under the control of Montgomery.
Apologies for the rather long post, but I think it's interesting info offering a bit of insight into how the material that gets left behind is put to use by the opposite side, as well as how chaotic and frantic the situations of both sides in North Africa really were.