What an inspiring thread, lots of great advice here. Have you considered the RAF? I had 20 great years and am now loving my second career in the commercial sector. I would never have been able to afford the training costs! Best advice I can give you is to believe in yourself and work damn hard! Read Ellen Macathur's book: 'taking on the world' - different topic but great inspiration for what can be achieved with nothing but determination.
Good Luck.