I really don't know enough to suggest/advise anything as you're already way ahead of me in software. There isn't much detail about what kind of teaching you're after, but it occurs to me that you may have to go back to school yourself to become current in your speciality or in an new one. I know that Adult Education is always after folk who'll teach in evenings. But you may need a "Certificate" of some kind.
These days, IT is moving at a heck of a rate. I'm surprised that there isn't some college that would want you. Perhaps, with DofEE rules, you have to have a teaching qualification different to the one(s) you have. Anyway, good luck. Mr F.