Yeah, Monster Mag was the home of the "GIANT SIZE PIN-UP - OVER 2 FEET X 3 FEET. OPEN IT OUT IF YOU DARE." You can download at least one issue in variety of formats via the treasure trove that is Archive.org
Thank you, Dem. Yeah, they were huge. Pretty sure all the ones I had were of scenes from Hammer films. Thanks also for the link. I can remember hardly anything about the mags contents so it will be interesting to see one again after all these years.
Unfortunately it's sample pages rather than an entire issue but at least they give something of the flavour.
From the first, I set myself against "literature"; the story was the thing, and no amount of style could persuade me to select a story that lacked genuine, unadulterated horror. For those who wanted something high-brow there was plenty.