This advert appears in Comics International 203, which has just gone on sale. (Click to enlarge.)
And that’s all I know at the moment. There doesn’t seem to be anything about it on the web-site of Hayena Studios, the company listed in the legal blurb up the side of the ad, and my limited Google-fu turns up no information from searches covering them or artist Huw-J.
For those who aren’t familiar with Garth, it was an adventure comic strip that ran for over 50 years in the Daily Mirror. The set-up was fairly perfunctory – Garth was a huge, heroic muscle-man who turned up, with little or no explanation, in all sorts of different times and places. Stories would veer from a western to an outer-space adventure to a contemporary horror story without taking a breath.
Peter O’Donnell, who created Modesty Blaise, wrote Garth for a while, but it is probably best remembered for the five-year run in the early 1970s when it was drawn by Frank Bellamy, who squeezed a remarkable amount of energy and dynamism into a single tier daily strip.
The International Catalogue of Superheroes has an entry on Garth here.
Update, 8 August See John Freeman's contribution to the comments section below for more information about Garth's planned return to the Daily Mirror (sort of).