To contact a venue that you've enquired to or made a booking with, just click on Enquiries or Bookings in the header and select the particular space you have put forward your interest to.
Click the arrow on the right hand side to reveal the details of the enquiry or booking. Click on the Actions button to reveal the Contact Venue button. Selecting this will show your on-site contact and their contact details. You can then call or email them as you see fit.
Alternatively, you can also contact your venue by clicking Contact Venue on your Booking Confirmation.