All assembled and working. Sort of :(

The esp8266 connects to my network and interegates the power meter and gets the right reading but....

It is somewhat unreliable the esp8266 appears to hang randomly sometimes it will run all night othertimes it will only do a few reads of the power meter. I had read that they are susceptible to poor power so I have added a 4.7uF Tant directly to the 3.3v pins on the ESP board but it doesnt seem to have made any difference.

otherwise...

Its up and running the extra bit of aluminium on the heatsink is keeping the temperature down. THe large sections near the screw driver are unnecessary - to far away from the Triac - Ill pull them next time I need to dissasemble it.

Ive been playing with the PWM output and trying to get the right balance of frequency and duty cycle to give good results.

Here in Aus our mains frequency is 50Hz. to minimize switching noise I have chosen a zero crossing Triac driver - ie only switches on and off at 0V. I have not implemented any zero crossing detection in the circuit to syncronise the PWM with the line frequency.