Is this a new record or has it been posted before, someone complaining about their flathead running too 'cold'.
I also had mine out today in the same weather.
I am using Robertshaw thermostats (160°) also, although in an 8BA .
Having noticed the same situation previously (would barely reach 150deg)
I installed cardboard appox. 40% covering the rad.
Now runs 160-170° as it should. No worries
