Enjoyable, even if it is undeniably sexist.
I remember discovering the television series of <em>'On the Buses'</em> when I was younger, via my grandparents, and loving it - admittedly at an age of not fully understanding the humour et al. I do remember watching this just about. It's amusing, nothing laugh-out-loud worthy but it's suitably entertaining.
Reg Varney, Bob Grant and Stephen Lewis are a very good trio. Lewis' Blakey is arguably the good guy, despite being portrayed as the antagonist - especially in this plot, given he's the supporter of women bus drivers. I gotta say, Grant's Jack is incredibly creepy. The things you don't notice as a kid, eh?
It does have charm, helped by it giving a nice exterior snapshot of 1960s/70s England and the buses of the time. The film, and series, is always most enjoyable - at least to me - when they are out on the road with the buses.
Obviously misogynistic and all rather dumb, but there are things it does reasonably well.