Interesting stuff, especially the first picture. If you look closely, the truck on the Left has its gun mounted - a lot of the crew are sitting on it. The car on the right seems to have its gun dismounted and winched up on that trapeze assembly between the vehicles - but why ? ? ?
The others are just sort of interesting... Pretty lady with flowers talking to her Tank Driving Boyfriend, and a Schneider mounting its transport truck. I have seen several pictures of Schneiders on their transport trucks, and of the transport trucks themselves, but of the tank actually driving up on to the truck seems like a rarity.
Although the E bay entry ascribes a date of 1925 to the Renault FT picture 1937 or even later must be the real date. The style of the girl's outfit dates it to then. Take a look at any photo of Mrs Simpson/Duchess of Windsor just after the abdication (11/12/36) to see what I mean.
Is that a 37mm gun on the FT17, or is he just pleased to see her? In the pic of the German trucks, the trapeze is a gantry, used for lifting heavy objects, so presumably they are part way through mounting the gun on the vehicle, which would drive under the gantry so the gun can be lowered into place.
The legs of the gantry appear to be mounted on the two trucks. Blowing the shot up the suspended gun appears to have a lot of garbage (twisted metal cables or pipes and the like hanging underneath it. The truck is copiously equiped with heavy winch drums at the front - I suspect that this is a slavage crew and the gun on the second vehicle is just that - on it not mounted.
Ah, yes, you're right. In which case it must be a sort of mobile salvage unit that carries the gantry with it and erects it on the back of the lorries on site. With the handbrakes very firmly on. Then what is the gun on the lorry on the left doing there?