Sussed the ACO's website re phone number log in's.
Ignore log in box on right, if you have not already ordered, you are not registered on their ticketing system yet.
When you have finished putting things in your basket proceed.
A page will appear with log in details in the top section, and new customer registration below.
Fill in both sections, with your phone number, and what password you want.
It should then work, you will be registered on the ticket system, and it will then take you to the payment section.
P.S. If you don't get the pop up on the tribunes section, try firefox.
Hope this clears things up a bit.