Find your Athlete Number
This is the number displayed against your name when viewing weekly results (Between your "Team" and "Age Group").

Print Your Tickets
Then just use this link to access the area needed to print your missing tickets. Select the week of competition ("meeting"). Select the event (leave blank for all events that week), and enter your athlete number in the box provided. You should then be presented with a page displaying all your event tickets nicely formatted that you can print (usually just File > Print from your browser menu).