Capt HJ Butler - Last Bristol M1c

[Clemshark]

Hi all.
First time poster so here goes.

I am researching a WW1 pilot who hails from my small home town in SOuth Australia.
His name was Henry John Butler ( AKA Harry) and he served in the RFC from July 1916 until he was released home to Australia in May 1919.
A brief rundown of his servie is as follows.
He was sent to the Oxford school of aviation then had various postings in the UK to further undergo training (I presume)
His postings as far as i can make out were 27 reserve sqdn, 49 sqdn then 10 reserve sqdn.
He then was posted to Turnberry (no 2 aux school of aerial gunnery) where he reportedly landed the first plane (a FE2B i think)
HE was then sent to Marske by the Sea and ended up Chief fighting instructor.
After the end of the war he purchased 2 aircraft from the air disposals board ( Bristol M1c - sn 5001 and an AVRO 504K)
He used these in SA for various things including stunting, some of the first airmails in SA, passenger flights and some of the first aerial photos.
Unfortunately he ended up dying from complications from a crash in the AVRO, although it took 18 months for the end to come.
His Bristol M1c survived and after an interesting history now resides in my home town. Although modified in the 1930's, it has been restored to somthing like original condition.
I am told it is the only original in the world ( there are 3 replicas)
I have peiced together most of this great story and have access to many hundreds of photos, letters, newspapers, family stories, etc, but still have much to fill in.
Can anyone help with some of the following questions?
Any info on Captain Butler or the squadrons he was in.
How do i find the records for when he bought the aircraft from the war disposals board in about Feb 1919? It has been written that he paid 2000 pound for the M1c but this seems high for 1919.
It has been reported that he also attached himself to operational sqdns and flew missions to France so he could study and bring back new German tactics to his pupils. How would i find these records as they dont appear to be in his file at Kew?
Any other advice on researching a WW1 pilot.

Thanks in advance.

Regards,

Les Parsons (Clemshark)