Jame,
Sorry to hear about your medical woes and disappointing news regarding your ATPL and ATC medicals. One of the beauties of the aerospace industry is that it is so vast that when one avenue closes to you there are still a multitude of others to choose from if you are still keen.
Air Traffic Control and Pilotting are both very different careers although granted they are both within the sphere of "commercial aviation." What exactly is it you are looking for from your future job? You'll need to think over exactly what you want to get out of the job before you can narrow it down. Is it most important for you to get your feet off the ground in a flying role? If so you might want to consider training to be a flight attendant. Granted the pay and kudos aren't the same as flightdeck crew but you are still working for an airline in a role which requires you flying around the world. Alternatively you might want to consider (as suggested by fernytickles) non-pilot military aircrew. I don't know exactly the medical requirements for aircrew such as loadmasters etc. but they might not be so strict as for pilots.
If getting airborne isn't the be-all-end-all then again the question becomes 'do you want to be actively involved around real aircraft from day to day?' ATC could have you sitting in somewhere like Swanwick where you never see an aircraft from one day to the next hence the reason for that question. If you do want to be involved on the real thing then in engineering a line maintenance job is the way to go or failing that some kind of ground operations job at the airport but bear in mind too that there are plenty of jobs in engineering (mostly on the uni graduate side) where you are working for aerospace manufacturing companies about as far from the real aircraft as you can get.
As i said the possibilities are potentially endless. But in answer to your direct query if you think you might be interested in line maintenance engineering look on this forum or airmech.co.uk for threads about getting started and the various licencing and training routes. There are quite a few so if you do a few searches you'll find them ok.
If you are still unsure about what other jobs and possible career paths are open to you you might also want to check out aviationjobsearch.com to give you some idea of what kind of jobs are on offer within aviation.
Best of luck!
