[Bluecortina]

There's a comment (weirdly not as a reply to you) that says "ITN's post-production department (now ITN Source) edited DuckTales episodes to remove commercial breaks on behalf of CiTV. Hence the latter's VT clock."

In 1989 perhaps this show was supplied by Disney as an NTSC copy and ITN were used to convert it to PAL as well as perhaps editing it for UK content regulations? Mere speculation on my part of course.