Well, Dinah Lawrence didn't take long to write up so I thought I'd put up a couple more pictures from the War Picture Library, along with the published versions. The first one I picked for the interesting variation: on the original artwork the boat is numbered 20, the published version has boat number 23. No idea why this change was made... perhaps to match the number of the boat in the strip itself.
The artist of both covers, above and below, is Giorgio De Gaspari, an Italian who produced dozens of covers for issues of War Picture Library in 1958-61 and then made irregular later appearances. He also produced covers for Sexton Blake Picture Library and for paperbacks, including at least one Tarzan cover for Four Square (Tarzan and the Castaways, Four Square 1552, 1966). Doing a quick search for information -- and there turned out to be precious little -- I spotted a short article about De Gaspari appears in Burroughs Bulletin 65 (Winter 2006), including a photo of the man himself. If anyone has access to it, I wouldn't mind seeing a copy.