How had Robin found the door in the wall?

It is a happily-ever-after ending for young Robin as he is reunited with his parents and given a high honor by the King on Christmas Eve. Finally, Robin will be taken back home to London where he can start life anew with his family and Brother Luke at his side. We are shown how Robin’s disability has actually lead to a whole new set of possibilities, or doors in the wall: not having to worry about wartime duty, Robin will have the time to work on his studies and craftsmanship.