[Si-Co]

I could understand doing it for a week or so but it must have been on air a good couple of months.  Wonder if the TV Times cast lists did the same.

No - she remained Huntington in the TV Times until episode 145 (when she left for Ireland) and was listed as Haversham when she returned around episode 156.

I’ve noticed a few episodes that appear to have the wrong set of closing credits attached, listing characters who didn’t appear. I assume these have been swapped due to tape damage as there were rarely any such anomalies on the original run (that I can recall, anyway). 

I have been meaning to point out something else I found interesting. The Saturday omnibus had two breaks - one was always at the end of the first episode, and the other would be at the original break from either the first or second episode. To avoid a “jump forward” in the action, they would always retain the break if the same characters or location appeared either side of it. Normally this practice worked fine, and one or other of the breaks could be cut out without characters teleporting across Liverpool, but in episodes 131 and 132 (which dropped a while ago now, I know), the pre and post-break scenes in both episodes featured the same characters and the scenes couldn’t be swapped around without affecting the story (a way to get around this I believe they occasionally did if necessary). So, in the omnibus we got an extra scene halfway through episode 132, featuring Alan getting ready for his night out singing “Roll Out the Barrel” and his mother looking in on him, unimpressed. That’s the only occasion I’m aware of that the omnibus featured an extra scene!

Episodes 155 and 156 had a similar situation where the same characters featured at both sides of the break in both episodes. Again, the scenes couldn’t easily be swapped so in episode 156, when the police arrive and chase Barry into the back garden, they just hold on the last shot a little longer and lead in with the dialogue from the next scene when he is being questioned (a practice very common now but for different reasons).