From January 1974: Another Mighty Marvel UK landmark moment: glossy covers!
I always think of glossy covers and the defining feature of British Marvel. They always helped the line standout when racked alongside the IPC and DCT weeklies and their (usually) bargain-basement production standards (of course, they were investing a lot more in originating new material rather than just recycling from the States).
So, it's easy to forget that in the early (and late) Seventies, Marvel's British weeklies had newsprint covers. THE AVENGERS, their third launch (September 1973), was the first to dabble in the new format... and their two existing titles followed at the turn of the year.
Glossy covers and 36-page interiors remained the default format (with a few exceptions: CAPTAIN BRITAIN sacrificed the glossy covers in favour of colour interior pages, FURY deliberately aped the low-fi formats of its war rivals and STAR WARS WEEKLY sliced four pages to make life easier for the pushed-for-filler Bullpen and to recoup the costs of the license) until the Marvel Revolution of 1979 tried to make Marvel's comics look the same as all the others.
STAR WARS WEEKLY and DOCTOR WHO WEEKLY retained their glossy exteriors throughout the Revolution (because it allowed them to showcase stills to catch the attention of casual browsers) and shiny covers returned (coinciding with the start of the SPIDER-MAN live-action TV show in the UK) in late 1981.
They remained, with the occasional exception (the experimental THE THING IS BIG BEN), throughout the rest of the history of the Annex of Ideas... although some formats were more glossy than others.