Back to heart rate training

If you've followed my blog over the last 12 years you will have seen that a lot of my training is done on heart rate.  I know some athlete's like to do it by feel but HR really works for me.  But it's not without its frustrations and I am currently going through a period of that just now.
I'm in winter training mode and not doing big miles and not doing fast miles.  Just consistent running with a lot of gym work.  I'm never going to have beach muscles as I approach 60 nor would I make the sacrifices required for a six pack, but I do need a strong core so I'm working hard in the gym.  I'll probably end up in an arm wrestling competition to see how my guns stack up!!!  But it's a great start to the day especially with the dark mornings and I can go running just as the sun rises.
But my heart rate is misbehaving and my coach has me under strict instructions to keep under a certain limit even if it means walking.  At first I thought it was my Garmin wrist monitor not being accurate so I bought a chest strap, but the other day it recorder 201 bpm.  If that was accurate I'd probably be calling an ambulance and I felt fine, however even when it settles down it's still too high.
So many different factors can contribute to the high heart rate; stress, booze, illness, hilly terrain or just running too fast (I doubt that!) but generally speaking I feel ok.  Sure the hills are tough but that's to be expected.
My instructions for the next two weeks are max HR 147, walk if going above this and take my HR as soon as I wake up.  This morning was the first day and it was 54 which seems pretty good for me.  I've been here before and it's settled down.  Before URR I had an ECG and everything was in order.  I'm not going to stress over it as that won't help but I have faith in my coaches training methods and I'll do what I'm told.  I just find it a bit embarrassing running so slowly but if I want to smash my goals next year then this is what needs to be done. Hopefully tomorrow's 8km will be on target and I can go and pump some more iron in the gym!