All right, here I am back with all I know, Ian!
First of all: I was wrong! The Tabloids that carried out the first bomb raids on the airship sheds in Düsseldorf and Cologne had racks for their Hales bombs! The relevant literature cited in Mario Kramp's book on Cologne in the early air-bomb-war are:
J.M. Bruce, The Sopwith Tabloid, Schneider and Baby. Historic Military Aircraft No. 17; in: Flight 72, Part 1, p. 733-
736, Part 2, p. 765-766, Part 3, p. 845-848
John Lea, Reggie: The Life of Air Vice Marshal R.L.G. Marix, Edinburgh 1994, esp. p.25 on.
Ian Castle, The Zeppelin Base Raids - Germany 1914 (Osprey, Raid No. 18), Oxford 2011, esp. p. 13, 21...
Bridget Pollard, The Royal Navy Air Service in Antwerp. September, October 1914, in: Mars&Clio. Newsletter of the British Commission for Military History (no date given = 2013), p. 1-15.
And an archival source in the UK National Archives, Kew, the after action report of Lt. Spenser D.A. Grey, who attacked Cologne: CAB 37/121/127. You can download this file:
http://discovery.nationalarchives.gov.uk/details/r/C6176513 .
By the way: Have you noticed this thread?
http://forum.ww1aircraftmodels.com/index.php?topic=3058.0I hope that will be of help to you!
Regards
Richard