[Oliver_W]

Originally Posted by Marsh.

Oh no, I don't want "proof" of where you've seen it.

I just wondered if there was more information, like a particular reason the order was changed.

I'll paste the posts below:

I think Episode 6 was episode 9 and Episode 8 was episode 6. Anyway, I think it was brilliant to put Demons earlier. We get to know Jaz better now and not in the penultimate episode of the series, it gave more sense of continuity for her character arc having Arachnids close to it, and, given the last two episodes not being everybody's cup of tea, having Demnos now was kind of needed.

and

Yes, it looks like it might have been changed for Remembrance Sunday, as this was an episode that featured World War 2 soldiers, and a remembrance for the dead (there was even a shot of flowers that looked like poppies, I wonder if that was added in)

It's possible there were other reasons, maybe they were just more confident in this episode, and thought it would fit better in this slot (the fact that this was IIRC the last one filmed but was shown halfway through the series indicates some confidence)
Or maybe Joy Wilkinson's Witch-hunter episode is much darker, and they thought it'd fit better later on.

Anyway as SBTB says it worked out for the best, as "Conundrum" wasn't that well received and this really, really was. We needed a new beloved episode Also people seemed to really want more Yaz, and this met their needs.