Here's something I found online (apologies it's not of the highest quality but I'm sure you'll get the idea): what appears to be a promotional poster, from MARVEL UK, sent out to US retails to announce the North American distribution of their key monthlies: CAPTAIN BRITAIN, STARBURST and DOCTOR WHO MAGAZINE.
The magazine-format Captain Britain was not a strong seller and shuttered after 14 issues. Starburst, after an extended hiatus, is still published today although Marvel dumped it not long after this poster appeared. Doctor Who Magazine, of course, survived the demise of Marvel UK itself a decade later and continues to appear, every four weeks, today.
M-UK subsequently started adding US and Canadian dollar prices to their weeklies but I've no idea how many copies actually crossed the Atlantic.