Can I stop registered users from creating their own events from the front end? I only want admin to create events.
Registered users can't create events by default, just organizers (you can set which ACL groups should be able to do so, by default starting with editor and manager joomla group).
can an admin create an event in the admin console and assign the organiser to a registered user, who can then logon from the frontend and see the attendees and manager the event?
You can assign events to any users, but to take a look at the attendees, manage events etc. they need to have the ACL rights (edit.own) for it.
Is it possible to pre-fill the booking form for an event with joomla registration details?
Yep that's possible, we offer full joomla user profile support (including the plugin with advanced fields).
Yves