From my experience (also a mature individual who recently obtained a PhD degree), I get rejection after 1st round of interviews (and I have done my homework reading and practicing for the job interviews). In general, their feedback “Good interview but there were other candidates who had qualifications with better match” (no need to be controversial and ask them if anybody had better qualification than a PhD)
I guess maturity (which is this case involves commitment and a strong desire to get a very good job) together with good education (PhD) are serious disadvantages to land a good job out there… It’s hard to quit career progression dreams…. Sad, but it’s a shame to see that a mutual benefit (employer/employee) is compromised by last century prejudice… Anyway, wish you luck to get that graduate job.