Gordon's Grandad's flag

Last time Layla was here, she spotted the little photo on the fridge showing Gordon's Granny and her friend holding up this flag. So I went to get the flag to show Layla. But I couldn't find it. A very important family heirloom. So have been looking ever since.
Today I found it. The little photo, has all the information about it written on the back, and states:

Susie and June 14/5/45

with the S/M "Sibyl's" "JOLLY ROGER"

6 Merchant Ships
1 Warship
8 Commando Raids
1 Secret Service job
8 Gun Actions
1 German Seaplane