There aren't really time frames. The email address you've been given should be a Dr - it's really just whenever they get a chance to look at it.
It's important to chase it up, especially if you're under a deadline for entry. Be extremely thorough with the info you've included; inevitably it'll be bounced back and forth once or twice because you've missed something.
In my experience, they got tired of looking at my info and just gave it the go ahead. It's a game of attrition -- so long as you get letters from doctors and evidence that you meet the standard, they can't refuse you.
Good luck and don't be put off -- can be frustrating but this is the easy part, so don't mess it up by not providing what they want!