Most people’s names, especially in government are in the format
firstname.lastname@department.gov.uk. This means that you can pretty
reliably guess that their name is ‘Firstname Lastname’.
When users are invited to Notify we know their email address already.
So this commit pre-populates the registration form based on this guess.
This is a nice little detail, but it should also stop the browser
pre-filling the name field with someone’s email address (which I think
happens because the browser assumes a registration form will have an
email field).