Hi Rob,
If you need combat reports there is a 400+ page file of these records for 54 Sqn RAF at the National Archives Australia website (including select months from 1940 & 1941). You might find some detail relating to 7th May 1941. Run a search using 54 Squadron in the keyword field and a file should be on the results list “54 Squadron - Combat Reports 12-31 August 1940, September 1941” (Series Number A11326, Barcode 322041).
http://naa12.naa.gov.au/scripts/ResearcherScreen.asp
regards, Drew H