ATPL or CPL etc gives you no licence cover in engineering but may get you a start as a technician. To become licensed you will need to sit the relevant exams as there are no exemptions for pilot licenses. Being the wrong side of forty may not be such a problem as eng have to work till 65 you know !!
Check out the CAA website for engineer licensing. Biggest barrier to getting a job in engineering will be the lack of experience.
Good luck