Pre-WWI militia & reserves

Hello, I'm trying to make sense of my gt-grandfather's service history and I was hoping someone could help me understand it.

The source I have has him a 2Lt in the Lincolnshire Regiment (militia) from 1905 to 1908, when he resigned his commission as a captain. In 1909 he apparently became a 2Lt in 5th (Special Reserve) Battalion, Royal Fusiliers (City of London Regiment), becoming a Lt in 1910. In August 1912 he becomes a 2Lt for the third time and is listed as an 'Officer, Royal Fusiliers (City of London Regiment)'. However, on the same day he is 'Appointed a flying officer, RFC' and as far as I'm aware his nominal regiment never hear from him again.

I'm confused because:
1) This looks odd. Why was he a 2Lt three times?
2) I'd assumed the militia and the special reserve were strictly part-time formations, but were their officers ever full-time? I ask because in a 1911 census he gave his profession as 'army officer'.
3) Did he in fact not become a regular officer until August 1912, and only then to join the RFC?
I recently looked at a militia officer who described himself in censuses as an 'army officer' and later as a 'retired officer' without ever serving full time - basically he was a man of independent means who had no 'real' occupation. So it does happen.

The militia ceased to exist in 1908 - if he did not immediately join the successor Special Reserve unit it may be that his militia seniority wasn't carried over and he had to start from scratch as it were. But I'm guessing.

I sort of recall that there were Special Reserve RFC officers pre-war.

Have you looked at the London Gazette (available on-line) and Army Lists of the time for clarification? And is there a P-file for him at Kew?

If you want to PM me his name happy to do some digging in return for a donation to Hols4H.
In those days Militia and the SR Commissions were backdoor methods of getting a Regular Commission.


Book Reviewer
My grandfather missed the boat for Sandhurst (due to his father wanting him to do something else, but all my man ever wanted was to be a soldier). So he joined the Militia May 1905, commission as 2/Lt dated 2.11. 1905 (4th N Staffs Regt). He was then given a regular commission into the E Lancs as a 2/Lt 27.5.1908 (Lt 25.1.1911).