From February 1978 (and the very first issue of STAR WARS WEEKLY): Another full-page piece of art dedicated to the movie.
SWW was released so late (almost a year after the American edition... which of course was released before the movie itself was even completed, much less released) because the film took more than six months to cross the Atlantic. And even longer the secure a national release across the UK.
The blockbuster was released in London on 27 December (but only on a few screens) and then took several weeks to build up a wide release. In those days, with the only outlet for TV advertising being ITV, it made perfect sense to release movies on a region-by-region basis and then shift the movie prints, and the TV advertising, to another part of the country.