ITV Schools on 4

The ITV Schools trailer, announcing the move to Channel 4, the only time I can ever recall it being shown on 4, was in June 1987, when, for one day, ITV Schools were moved onto 4, to allow for coverage of the General Election. I can't recall it ever being shown on C4 at any other time. Was it shown in junctions between normal C4 programming? Also, did any ITV companies show the trailer outwith schools programming?

It was certainly shown by some ITV regions between morning programmes over the summer, and of course during schools programmes towards the end of the summer term. Not sure if it was ever shown on Channel 4 except the occasions that schools were moved to Channel 4 that summer term.