This epsisode made me LOL.. Thank you!!! Snacks: lamb with cauliflower cheese & mash (it's dinner here). FYI - The "saucy lady" is Wendy Richards, HUGE "bit of totty" on TV in the 70's, also known (in the UK) as Miss Brahms (in Are" You Being Served") and Pauline Fowler (in Eastenders).
For me, Mrs. Mainwaring is like Columbo's wife. The warden's line about that sort of party is hilarious. It was Wilson's fault for mentioning the bedroom. He could've just said they're upstairs. Mainwaring is snobbish about stuff so I think he's ashamed that his father was a simple tailor. He couldn't lie and say he was a lord or something, but he stretched the truth as much as he could.
Jimmy Perry had always intended Mrs Mainwaring to appear, but Arthur Lowe insisted it would be better to have her 'off-screen". so the episode was rewritten. Mrs Mainwaring did finally appear in the 2016 movie (Set after the series), though whether it's canon is debatable, as it contradicts the events of the final episode.
Shame that Clive Dunn couldn’t bear Arthur Lowe given how devoted Jones was to Mainwaring. Dunn was a socialist , Lowe very conservative. Perhaps there was more to it than that.