If you have a PPl then follow through on your pilot course and get an ATPL and be an airlines pilot.
Way better than engineering.
However if you're still insisting to get to the engineering then here's some tips as to what you should do:
1-find a job as an unlicensed mechanic.
2-work for 2 years and keep a CAP 741 logbook with you in which you would write all the tasks you performed and get the engineers to sign for you.
3- after 2 years get hooked to an EASA training school and attend the whole curriculum of a part 66 license training.
4- once you pass all your modules together with your logbook you'll then meet all the requirments to applying for a B license so apply and get one and thats it.
Sounds like a huge and aggravating story that's why I highly recommend that you follow through on being a pilot, pilot job is much better in terms of pay and workload.
Good luck at whatever you choose