Hi

Have not used it myself, but a friend was staying with us last year, and had a broken leg.

He travelled back to the U.K. using them from Reus. No problems at all. They must be told though just after booking. They reserve a front seat for you and your travelling companion(s).  

They embark you last, and you leave the plane last as well. He had problems at Luton though, as after being taken through passport control he was just abandoned in baggage reclaim. Not Ryanair’s fault – it was the airports. No extra costs and cut out a lot of ques and stress. They did not ask for any documentation or type of disability.

Hope this helps
:)