The new site must surely be one of the bigger e-commerce disasters in the latest years. I still have not seen anything about in the on-line news.
I believe someone will be sweating a lot right now.
Also I do not understand why Ryanair does not have a roll back plan in place.
There must have been an enormous amount of penny-pinching. From what others have said it looks as though they may be using the infrastructure for the new website/booking system. That adds an enormous amount of risk to the projet. In an ideal world the new system would be built on a new production platform and existing data migrated across. Once the migration was complete the new servers would be added to the network and begin taking bookings.