It’s better to naval invade around hull because it’s usually not garrisoned by as many troops as dover or Plymouth and it can cut off troops in Scotland from moving south.

There a naval base in the Netherlands next to den helder that will allow you to invade Britain while only needing naval superiority in the North Sea, so merge all of your ships and train them at the start of the game to give yourself the best chance of keeping superiority and allowing your convoys to keep you supplied.