Can someone else renew my passport for me?

Hi
I am 15 year old British citizen who lives abroad.
My passport needs to be renewed but because there are problems with the passport centres in Dusseldorf and Paris, my parents have decided to get it done in Britain instead.
My passport renewal would take at least 8 weeks in either Germany and France and I don’t have that kind of time.
August 3rd – 28th I have flights booked to see a friend who is dying of cancer. So I’m kinda pressed for time.
So my parents contacted a friend of theirs in Ireland who would be willing to do it for us.
We would send my passport photo and forms and it would get to her in about a day.
She would have then already planned an appointment with the passport office to renew my passport.
And then it would take a week to renew it? And then she would send it right back to us.
Is this in any way illegal? And do you have any idea if it would work or not?
Does one of my parents have to renew it for me or can it just be anyone since I am under 16?