Alexander - why have you got it into your head that people will pay to go to the memorial when you have been told they won't several times !!!
People coming to a memorial will likely pay for souvenirs, give donations, use a shop/cafe. If the Drop Redoubt or other fortifications are open people would pay for access which will pay for the upkeep.
Enhancing the visitor attractions (and shops like DTIZ) in Dover will keep people from moving out of the area to spend their money and encourage more to the area to spend their money. Simple economics
