For those who may have acquired the new style thermostat from CIP1 and been confused by the section of their instructions which goes:
"There is a locking pin on the thermostat and a hole in the bracket to stop the stat from rotating"
There is no hole in the bracket as the locking pin (or tab) is supposed to hook over the edge of the bracket. So, it should not be necessary to make any modification. Just thought I should pass that on.