[Andrew]

There are a few Orders of Battle, including the Balloon Sections, in the SHD Archives at Vincennes in Paris, but I can send you those if you wish, and they are likely to be in the TNA.
Be aware that there is a large quantity of documentation relating to Balloons at Kew, and it is poorly organised.
Consequently documents relating to a particular section might be indexed under the section, the company or the Wing, or under general headings.
Some of the files don’t mention balloons at all – i.e. the massive RFC correspondence files in AIR 1/362/… et al (which include orders for each section to depart for France, and list of officers)
If looking for something specific it is best to have the OOB’s as the organisation changed frequently.
I can send you copies of what I have if it helps if you contact me via [email protected]