Brian,
Wikipedia has a story too about the use of the RN Walrus by M.F. 11, the Romsdalfjord Air Group and return flight to the Shetlands.
Try
www.en.wikipedia.org/wiki/Høver_M.F._11 for an interesting read.
(I had to figure out the Scandinavian "ø". You get it when you press Alt and type 155.)
Regards,
Leendert
Brugge/Belgium