I've been watching the old episodes, and I had forgotten how much more I enjoyed them when we had Lady Felicia and Sid.
Bunty just doesn't really work for me. I feel like they tried to combine some of the characteristics of Felicia; flirt, men fall over themselves for her, has money, butts heads with Mrs. M, and characteristics of Sid; good with cars, rebel, picks locks, likes to get into trouble, and none of it really works.
Felicia and Sid they just worked better and IMO are better actors than Bunty. In The Skylark Scandal, I found myself wishing that the actress playing Hetty had been cast as Bunty.