Having a senior moment here, can you help!
I'm trying to apply for a marriage cert. but having difficulty figuring our what I should be asking for and what I should be paying...

Here is what the application payment information says..
Full certificate of birth, marriage, death or adoption by post / phone / fax
£11.50
Full certificate of birth, marriage, death or adoption (with GRO reference supplied)

by post / phone / fax
£8.50
I'm applying by post. Looking for parents names.

What is the difference??