It was based on the Southern Television TV show which, in turn, was based on the original series of books by Barbara Euphan Todd. It was timed to coincide with the launch of the show's (starring, of course, Jon Pertwee) fourth season on ITV.
Producer Southern Television lost their ITV franchise in the shake-up of 1980/ 1981 and went off-air at the end of '81. Their successor, TVS, didn't continue with the series and the fourth year was the last. Marvel UK presumably knew all this when they acquired the license although, perhaps, they hoped that another ITV contractor would continue with the series.
The first issue, pitched at younger readers, came with a great freebie: a flexidisk featuring the show's memorable theme tune, as performed by Pertwee. That alone would make it worth buying (although, sadly, my copy has long-since parted company with the disk). Records were not a frequent Marvel UK giveaway although - in the eighties - they launched the CARE BEARS and ACORN GREEN with similar giveaways.
A Worzel strip had previously appeared in ITV's own LOOK-IN weekly along with occasional features (memorably the lyrics to the theme).
I'm not sure how long the monthly ran but it was subsequently replaced by a weekly version which was based on the books with no overt links to the TV show. I imagine Marvel went straight to the book publishers for the license rather than whatever remained of Southern's licensing operation.
The TV show returned in 1987 for two more season produced in New Zealand which saw Pertwee (along with Una Stubbs) reprise their roles.