After all, your research has shown that there may be a Romano-British or Medieval settlement there!
As seen on many forums, there are many ways to ask for permission, whether that be face-to-face, letter, telephone call or email.
Some people don't feel comfortable with a face-to-face meeting so may write a letter instead.
Unfortunately, this phase of the formulae can be quite disheartening when a permission is rejected.
This is where resolve is needed and a strong motivation to move on and look forward to the next request. After all, it may be a yes.