For the first ten years or so,. Channel 4 was effectively ITV2, or wouldn't have happened since.
I recall that C4 were the first to introduce a soap omnibus (for Brookside) to pad out their rather empty schedule. I don't remember them having Corrie on there, but it doesn't surprise me as ITV got the advertising revenue at the time, and I suppose it would create some, rather than having that "Programmes continue shortly" card.
Corrie only appeared the once - as Steve/nwtv2003 states above, an unscheduled omnibus was shown on the Sunday night as the weekday episodes had been disrupted by industrial action at Granada, and had been shown Wednesday and Thursday at 7.30. I think ITV wanted to give viewers who may have missed one of the episodes another chance to see it. Quite surprising it was shown on Four rather than ITV, especially as C4 didn’t have full UK coverage in early 1983. I expect there is a story behind that.
Cut out the coupon in your TV Times!