When creating Resource Mailboxes for Rooms, they are created with the Booking Delegates Booking Requests set to "Use customized settings to accept or decline booking requests"
 
Is there either:
 
a) A way to change this through the HC10 console on a room by room basis once the Resource Mailbox has been created.
 
Or
 
b) A way to set this as the default setting when a Resource Mailbox is created.
 
Regards.

Yes, this can be changed from within HC panel  after resource mailbox creation from HC by navigating to the dashboard of resource mailbox at : Provisioning  >> Exchange Organizations  >> Resource Mailboxes >>  Dashboard and then selecting the option "Accept Or Decline Booking Requests Automatically" under Booking Delegates tab.