Thank you for the replies so far. I'll probably give it a try as well although my knowledge of VBA is limited at best so I don't hold out much hope.
I'm just wondering whether another alternative would be to use a meeting room Sharepoint site template?
I am aware that there is no functionality for Outlook to limit the number of 'accepted' attendees to a meeting request. Is there a way of doing this using VBA or by installing an add-in?