The old battleships you have are crap, use them as scrap metal or to guard the Canadian coast. UoB ai tries to land in Canada, but you can stop them if you destroy the navy and leave a few ships behind to take care of the trannsports. I would argue that Navy>Army>Air Force. I did not use any bombers, just a few fighters to stoptheir aircraft. And I think you're underestimating the UoB Army. Unless that's just your first "wave", and you'll send more after you take the beaches.
i had another 10 divisions to land after that, including 2 armoured divisions. the bombers were to be landed in britain to help the advance. i think in order to succeed i'd have to completely start again and build a giant navy, because the ai's navy was stupidly large and effective. and i did exactly as you said with the old ships - they were to guard the coast though they'd have been wiped out too if i'd sent them out. well done on doing much better than me, though