Trying to determine if we can entertain ourselves for 24 hours in Dover, prior to shipping out, or if we should stay in London overnight.
Other than seeing the cliffs, I don't think there is much in Dover except the port. Your time might be better spent in London.
Dover isn't what it was. In fact the town itself is getting slightly unsavoury.
If London doesn't take your fancy you could always try an evening in Canterbury. It's a short hop from Canterbury to Dover. There's plenty to do and see in Canterbury.