Thanks. Sorry, I didn't see the feature request before posting.
Hi - I'm afraid it's not currently possible for us to automatically recreate directions in reverse, as these are generated as you plot the route. There is an item on our Feature Request list (number 15) to automatically generate directions for routes that don't have directions but we don't currently have a way to do this.
After I reverse a route, the route map appears to be normal but the directions and GPX download are blank.