Despite the fact that I am talking to myself....
I have now looked at the collection and it may well be of interest to someone who specialises in that period.
It includes a button and "wings" from the Instone uniform (plus the information that Instone were the first non-military air operation to introduce uniform) and some timetables which slightly piqued my interest in that they appear to have advertised and priced a route to Prague, but they never seem to have flown it (and then timetables a month later have Prague removed.)
There are other little gems in there, like a payload vs range sheet for one of the aircraft (Bristol or Vimy, I forget which) and an interesting guarantee to deliver passengers and mail to Paris providing that the "weather is reasonably suitable for flying." I love the idea of it being
reasonably suitable.
There is a nice correspondence in there concerning a passenger who was taken out to Paris in the very early days (1920 AFAIR) but could not be brought back because the engine had blown two valves, which took "4 or 5 days to repair". But the passenger is reassured that the company is buying an aircraft with two passenger seats and they hope to bring him back soon!
There are also numerous photos and postcards showing operations at "London Air Terminal" (which I think must have been Hounslow) and Croydon, manufacturers' advertisements for various aircraft and similar memorabilia.
Let me know if anyone is interested.