I'm a mentor. I have an ECT1 at the moment - he is finding his feet but not strong if I am honest so taking up a huge amount of time.
This year, I am also delivering the SCITT subject knowledge sessions (x 10 days across the year).
I'm a HoD of a core subject so in some ways, the extra goes with my job. I'm late thirties so younger than you but I still find it very tiring mentoring. Especially for a trainee or very new ECT who isn't strong.
The subject knowledge stuff was given to me and sold as good development/good for the school and dept. All this may be true, but I get no time what so ever to do the planning of these training days. I also have a form group and have to run two extra curricular groups per week.
I've also been told, only since we came back in September, that I have to minimise cover on the days I have the trainees. So, what is actually now happening is I am using my PPA/management slots to deliver, teaching my classes while they observe me/others in dept.
I have one this Friday and should have 3 management periods. Now though, my day is;
Arrive, set up, make sure ECT1 who is attached to my form knows what he is doing with morning form as he won't look for himself.
Deliver to trainees through form P1 and P2, spend break with them and also set up my P3 lesson.
Teach my P3 lesson while they do a task/observe.
Back to them P4 to reflect and do more input.
Spend lunch with them.
Teach P5 while they observe.
Quick final debrief after P5 and then dash to CPD for 1 hour and 45 mins.
It's insane!
Sorry this has turned into a rant but I absolutely sympathise with you. I want to develop new entrants to teaching but the demands now are absolutely mad.