For such a large organisation not much is know about Malboro but they do still have a website https://www.marlboroughbike.co.uk/road-bikes.
Marlboro Cycles was a major British bicycle manufacturer based in Wednesbury (and Darlaston) in the West Midlands during the 1980s. Backed by overseas (Saudi) ownership, it grew to become the second-largest bicycle producer in the UK behind Raleigh before folding near the end of the decade.
Malboro manufactured own-brand cycles for Halfords in custom liveries and built classic red delivery bicycles for the British Post Office. In late 1985, Marlboro took over the famous historic W.F. Holdsworth cycle brand, moving its production to the West Midlands for the 1986 “Marlboro-Holdsworth” range which continued into 1987. The partnership was short-lived, and the business assets—including the Holdsworth name—were sold on to Falcon Cycles in 1987 before the Marlboro operations completely wound down.
Some links to Malboro:
https://forum.cyclinguk.org/viewtopic.php?t=43438
https://www.facebook.com/groups/vintagebicyclesuk/posts/2222004971373700