Hi Paul,
It’s from ‘Flight’.

The first time ‘Flight’ published the ‘War Office Summary of work’, would appear to
be in it’s 8 March 1913 edition.
It is signed War Office, March 4th (see image).

In the same 8 March edition, under the heading ‘From The British Flying Grounds’,
is ‘Flight’s’ own report on the R.F.C (see images).

I think this answers your question.