Here is a picture of the reverse of Wing's bar on his DCM.
It is engraved to represent the Bar to D.C.M. London Gazette 22 August 1918: ‘For distinguished service in the Field, in connection with the campaign in German South West Africa, 1914-15’:- 0134 Sqdn. S.M. F. W. Wing, D.C.M., 5th Mounted Rifles (Imperial Light Horse).
DCM VR (78258 Serjt: G. E. Bowhay. R.G.A.) officially impressed naming
DCM London Gazette 27 September 1901.
George E. Bowhay attested for the Royal Garrison Artillery and served with 6 Company, Western Division, R.G.A. in South Africa during the Boer War (awarded the Queen’s South Africa Medal with clasps for Cape Colony, Transvaal, and Laing’s Nek; and the King’s South Africa Medal with two clasps). Advanced Battery Sergeant Major, he subsequently served with the Royal Garrison Artillery during the Great War on the Western Front from 8 October 1915 (awarded a 1914-15 Star trio).
Note: Bowhay’s five campaign medals; his Ed VII LS&GC and a DCM with ‘officially engraved naming’ (and therefore most likely a later replacement) were sold by DNW in May 2018.