Danny,
With rare exceptions, citations for the DFM were not published in the London Gazette. Those that were can be found in I T Tavender's The Distinguished Flying Medal: A Record of Courage 1918-1982, published by Hayword, 1990, ISBN 0-903754-43-6. Out of print, but copies can be found on the used book market. There are not a lot of actual citations.
After he published the above, Tavender did a heavy duty review of the contents of Air 2, which contains the recommendations for awards in World War 2. He collected these recommendations (usually from the Squadron CO, or the Station CO) into two massive volumes: The Distinguished Flying Medal Register for the Second World War with Official Recommendation Details. Published in 2000 by Savannah, ISBN 1-902366-03-4 for volume 1 (A-J) and 2 (K-Z), Rather expensive, but still in print.
http://www.savannahpublications.com/ It is expensive, I hope you are fully employed. Savannah also published a one volume collection of the citations to the Military Cross for airmen in WW1, and another massive collection of the citations for the DFC 1918 to 1995 (Nick and Carol Carter), which appears to be out of print from them.
Lock your wallet up!
Enjoy (if you can get copies).
Frank.