Robert (forum member rcm612) messaged me with a link to a US site selling WWII video footage and single frames taken from that footage. Unfortunately they charge a fortune for the high resolution video footage but there are nevertheless some quite interesting bits of footage on here with many Flowers appearing in the films. Robert sent this link http://www.criticalpast.com/video/65675061301_Allied-convoy_World-War-II_British-gun-crews_barrage-balloons which has a lovely shot of a modified Flower from around 00.45 with the full ship visible at 00.59. If you go to the frame list below and enlarge frame 59 you can just about make out a pennant number - possibly K65 HMS Myosotis. If anyone can positively identify this ship do let me know.