Yes, that is the UK Fontana cover. If I recall, this one is compiled from two sessions - side 1 has tracks from 'What The Dickens' and side 2 tracks from a slightly later session.
It doesn't appear so; it's a conceptual album, the contents being a continuous suite. It seems to have been recorded in 1967, since the liners make a point about Dankworth's "very newest orchestra" and mentioning a May 1967 gig at Ronnie Scott's. But I think I will seek out 'Dickens' and the other of Dankworth's 60s big band dates too.
Now listening to the Blue Mitchell Milestone twofer, the side from 'Smooth as the Wind'.