Hi Henk

I'm not aware if any the of following were on your 1939 list, but I have just come across these while researching at Kew:

AC2 Thompson 621154 149 Sqn Died of injuries following motor cycle accident Newmarket
AC2 Hoey 615404 149 Sqn AG - seriously injured in same accident

AC R.G. Davies 528576 144 Sqn. Died of injuries following road accident Scunthorpe

LAC Ernest John Naylor 567513 149 Sqn. Died in hospital following car accident on Epping New Road.

LAC John Travers Smith 520179 149 Sqn Died in hospital after being knocked off bicycle by car on Newmarket Road.

Hope this helps