Search your inbox for a booking confirmation email sent from

Found the email

Once you've found the email, the tickets will either be attached or accessible from your account.  Quick access to your account is by clicking 'Manage booking'.  

Not found the email

The booking confirmation email is not essential for travel as long as you have the tickets.  If you are registered then login to My Bookings or within our App under 'My Tickets' to get access to the tickets.