In the first Inn scene, just after the "looking for rabbits again, Friar?" line, sitting behind the jokester are two men who laugh with him, one wearing a yellow turban. In the next second, as Dream walks past them, this man has vanished.
During the opening scene on the bench, the woman in green on the next bench changes shoes from running shoes a couple of times, into open high heels after the Mary Poppins quote.
When approaching the inn in 1989, the background shows a scene of Canary Wharf with a completed Canada Tower (the one with the pyramid on top) surrounded by similarly sized skyscrapers. In 1989, Canada Tower was only half built and there were no other skyscrapers around it of a similar height until the late 1990s.
In the 1389 tavern three men are seen with clay pipes, including Geoffrey Chaucer and the man sitting opposite Hob. None are actually smoking although Hob's companion lights his pipe with a taper. *This is 160 years before tobacco was introduced into Europe*.
Curiously there is no sign of any tobacco use in the White Horse of later centuries until 1889 when Robert has a cigar and ashtray. The cigar remains unlit.
Finally, in 1989 there are cigarettes and smoke. But no one is actually seen smoking.
In the 1889 tavern scene the piano music on the background is the 'Passepied' from Claude Debussy's 'Suite Bergamasque'. Debussy only started composing this piece in 1890, and it wasn't published before 1905.
Death misquotes Mary Poppins. The correct quote is "Feed the birds and what have you got? Fat birds!"