The date is significant: this issue appeared in June, around the time that RETURN OF THE JEDI was released in British cinemas. Marvel made the most of the marketing moment by returning the monthly to a weekly schedule, adding colour interiors for the first time (thankfully ironing out - literally - most of the problems that accompanied the first colour weeklies, see here for more), reverting to issue one and renaming it RETURN OF THE JEDI.
The all black & white line-up consisted of a reprint of the 71st US edition supported by THE FURTHER ADVENTURES OF INDIANA JONES. Both story lines, now accompanied by Marvel's ROTJ adaptation, continued into the new weekly. See here for the history of Indy at Marvel UK.
Cutting THE EMPIRE STRIKES BACK WEEKLY (as it was then known) back to monthly has always been perplexing. SWW was a cash machine for the Annex of Ideas in the late seventies and it's hard to believe that sales dropped so far, so fast, after the release of the second movie that they had to cut the schedule to monthly to keep it alive as they did with DOCTOR WHO WEEKLY and FUTURE TENSE. I think it's more likely that since Dez Skinn's 1979 Marvel Revolution (see here), Marvel New York were no longer willing to create the additional strips required to fuel a weekly schedule and the London office were unwilling or unable to pick up the slack (although they did dabble with a run of UK-created strips) and cutting back to monthly ensured they roughly kept pace with the output of the US office.
The ROTJ weekly clocked-up another 155 issues until succumbing to falling sales and Marvel's decision to drop the license on both sides of the Atlantic.