It was an odd one that is for sure. I ended up researching all about the commedia dell'arte thing it was based on and after that it made a hell of a lot more sense. Like in the show itself said, its a drama teacher's wet dream. Was perhaps a little too clever for itself but had more a ring of the Zanzibar episode rather than others. Won't be one of my favourites by any stretch of the imagination but was alright.
Also listened to the Inside Inside No 9 podcast and that explains that during lockdown last year they wrote series 7 and they ended up filming the more "COVID friendly" (i.e. smaller cast sizes) episodes and this one was initially designed for series 7. They confirmed that this season consists of 2 "series 6" and 4 "series 7" episodes.