The Police Advisor's Office appears to have been a metamorphosis of Dublin District D Branch which was transferred to Police control in Jan 1921. Z Coy certainly existed, and ADRIC men were post to it, it appears to be a group of ADRIC men seconded to the Police Adviser's Office, D Branch, run by DHM Boyle . As Intelligence was concentrated in the Office of the Chief of Police, numbers rose from 1 man in 27 May 1920 to around 150 by 23 Jul 1921 (exclusive of Special Branch and outside agents)
It is difficult to know whether Z Coy of ADRIC was controlled from here or was operated by the ADRIC
There was also the Police Authority Information Section run by Pollard and Darling
A Book giving Director of Intelligence's Orders dated 11 Dec 1920 gives an office organisation of
1921 Feb 19 A memo from DHM Boyle to Colonel Haldane. Haldane was not very enthusiastic about this proposal
It has for a long time been apparent to me that we cannot get the best results out of our work in Dublin unless and until we get full value from the Special Branch of the D.M.P. To attain this end it is my opinion that, that Branch should be placed under the same control as our own special officers, The only question is how to do it.
I do not know how long Colonel Johnstone has to serve towards his pension, or whether indeed he would be inclined to retire. Provided, however, such retirement or another appointment under the Crown was possible for the Chief Commissioner, I would suggest that Mr. Barrett be appointed to fill his place with entire and sole charge of the Uniformed Branch of the D.M.P. I would further suggest that the Special Branch, i.e. "G" Division, be worked as a section of this Office under Lieut. Lockhart.
I think you will agree with me that this young officer has proved himself during the last eleven days to be capable of far higher duties then those of a secretary. His perseverance and tact, his acquired knowledge and experience of the general work have stood out in an amazing degree, and it is, I consider, only fair to him that he should have the chance, which he fully deserves, of running one portion of our Intelligence Organisation.
O's secretariat would then consist of Mr. Craycroft and Miss Adye, while the office, over which I preside under O would combine all the Dublin Special work under two sections, of which Lieut. Lockhart and Lieut.Hyem would be the heads, Capt. Boddington being under Lieut. Hyem in charge of the outside work where our own people are concerned.
The advantage of this suggested arrangement to the whole Organisation and to the Government generally, as well as to O's in particular, would, I think, be apparent after very little reflection.