Police Gazette -Friday 10 May 1918
-ARTHUR FLATMAN aliases Fredk. Collinson and Arthur Fredk. Collinson Flatman. C.R.O No. S/ 165444, age 43, ht 5ft 5.5 inch, c. fresh, h. brown, e. blue, three scars top of forehead; dress, grey mixture suit, blue overcoat, greenish trilby hat, black boots. An agent; native of London. Pre. Con. of forging and uttering a cheque, and a minor offence at BRENTWOOD and in MET. POL. DISTRICT
Police Gazette – Tuesday 21 May 1918
40. – ARTHUR FLATMAN, C.R.O. No. S/ 165444, was sentenced at West London Pol. Ct., 13.5.18 to 3 mos. Impt. See Case No. 10, 10.5.18
There do seem to be quite a few references to him in the papers (from British Newspaper Archives)