What is not clear on Ryanair's website is whether the customers it has let down in its usual cavalier fashion have any other option than to accept the refund. The ATUC site refers to either a refund within 7 days or
Re-routing to your final destination as soon as possible or, if you agree, at a later date. (If the airline flies you to another airport in your destination city then they must pay for the transfer to the airport you were booked for or to another close-by point of your choice)