The Cromarty was suggested to the Royal Navy in 1918, first flown 1921. It was an improved/redesigned version of the Felixtowe F.3/F.5 flying boats already built in license by Short. It was not succesfull, 2 additional aircraft (N121 and N122) were cancelled, N121 already partly built.
NOTE: The observant viewer will not doubt see "N126"
on the vertical tail, but this is a actually a "0" obscured by
a fitting of some sort giving the appearance of a "6". Per
the book 'British Military Aircraft Serials 1911-1971' by Bruce Robertson
confirms that the only Cromarty built was N120, and that N126 was a