MAURITIUS STEAM NAVIGATION CO. LTD.
image by Eugene Ipavec, 26 August 2008
Brown 1978 shows a rectangular flag; Ipavec’s FOTW illustration is described as a variant.
The BISN-site flag is a white swallowtail completely edged blue, with a red diamond touching the blue borders and a blue M inside.
Mitchell also places M552 on the J. Rogers & Co. card, while qualifying the vessels as Mauritius Steam Navigation’s.