No flag is listed for Imperial & International Communications in the cited account; yellow funnels are presumed.
Following the 1928 Imperial Wireless & Cable Conference, Imperial & International Communications was formed on 19 September 1929, combining 22 cable companies and four radio-operating authorities. The source names Marconi’s Wireless Telegraph, Pacific Cable Board systems, Imperial Atlantic Cables, Post Office Overseas Beam Services and Eastern & Associated Telegraph interests. Marconi’s business had begun in 1897 as The Wireless, Telegraph & Signal Co., renamed in 1900. Prothero’s account specifies Eastern Telegraph, its Extensions and Associated Companies, and Pacific Cable Board. Western Telegraph was taken over in 1929.
Keep the explicit scope label independent; no alias or company identity is inferred.