What midlife career change to earn £100k/pa?

On the back of the "What job to earn £100k a year?" thread, what jobs would you recommend to someone aged around 35-45 years old who wants to earn around £100k by completely changing careers?

I earn around £45-55k per year as a senior support worker in forensic support. I work crazy hours to hit these numbers, including at least 2 (sometimes 4) overnights away from home. Not in London.

What did you do, and how did you get there?