Well, I must speak up for historical accuracy here.
Quoth Elphicke: '...this is the town that repelled Julius Caesar and saw off Napoleon.'
Napoleon planned, but never attempted, an invasion of Britain. Pitt The Younger approved and initiated the building of fortifications and defences at possible access points (Western Heights, Hythe Canal etc.). In this context, the claim that Dover 'saw off' Napoleon is mere crowd-pleasing puffery (something I would never have expected from CE).
He's on firmer ground with Caesar, though. The sight of warriors on the cliffs at Dover forced Caesar east to Deal on his first invasion but, despite a successful landing and some fighting, the weather intervened and he sailed back whence he came. The next year (54 BC) he avoided Dover altogether and headed to the beaches east of Deal, where he landed without a fight (plus ça change). Caesar made some headway but, again largely owing to the weather and problems in Gaul, he sailed away, never to return.
By the way, can you see Dover from St Margaret's?