it's no big deal I just wasn't aware of it but Qatar emailed me in plenty of time to organise it and thankfully there are no restrictions for getting back to UK, travel is definitely becoming easier but unfortunately the prices aren't!
Also at the start of your journey the airline will arrange assistance at check-in to get you to your departure gate. I have arthritic knees so it's a great help trying to navigate the massive airports we need to travel through. Good luck with your surgery.
If you have requested mobility assistance through your airline there will be someone waiting with a chair as you leave the plane. They take care of everything including fast tracking through immigration and getting your luggage. They a very good and helpful.