Just been reading the book "British and American Artillery of WW2 by Ian Hogg", it mentions on page 82 that "the ammunition was separate loading with a cased charge in a parallel-sided brass case 35.8 in long".
Having just typed this into the google converter.........
35.8 Inch(s) = 90.932 Centimetre(s)
So short of someone actually measuring the Bovington case to confirm it would seem to be 909mm long or thereabouts.
Dave.