The flag is red with a white diamond extending to the edges and red “FB”, the letters about one-third of the flag’s height in the quoted 2:3 rendering. Sources disagree over punctuation: many omit dots, Stewart places periods after both initials, and Merchant Ships 1944 has a single mid-height dot between them. Brown’s quoted account gives a black funnel. The suggestion that periods were dropped as a design improvement is van den Muijzenberg’s interpretation, not an established chronology.
Marinart and Ocean Ships assign this funnel to the subsidiary Bolton Bulk Carriers but do not mention a black border to its diamond. Mitchell omits both border and letters, with a Glasgow sighting in May 1968 that might instead refer to B440.
The company apparently began in 1885 as Bolton & Kenneth, later Frederic Bolton & Co. trading as Bolton Steam Shipping. It acquired Glover Brothers in 1943 and operated North Yorkshire Shipping vessels, subsequently listed under Bolton itself. Ships were named after painters beginning with “R”. Carnival acquired Bolton through Nosira Shipping in 1982 and sold both companies to Mountleigh in September 1987.
U.K., London.
Keep the explicit scope label independent; no alias or company identity is inferred.