Here you go, 39 pages of "Am I too old" for you.
Personally I can't see how that many people can afford to have a fATPL much before 30 so I think you'll be fine. People are worrying about getting jobs at 40+ and still manage to get a job at 44 / 45 / 46 years old. I think the airlines will take into consideration your Mechant Navy background, harbour pilot skills, HND, and life experience and form an opinion on that.
Good luck fellow Welshman.