Wing Cmd Peter Brett
Following your post, Wing Cmd Peter Brett did indeed know your Grandfather and was his Wing Man. In the group photo posted by you, he is the first man on the left, middle row.
Sadly Peter Brett died this morning ( March 02, 2013) aged 92 at the Maison de Retiermant, Saulieu, 21210, France.
Wing Cdr Peter Brett was unable to write his memoirs but talked about his wartime service and these memories can be heard spoken by him on youtube. Search Peter Brett.
Lest We Forget.