More kiln trouble

A couple of months ago, I was getting a tCL error on my kiln and after some advice from Cherry Heaven to make sure it's warm before I turn it on, the kiln has been behaving itself nicely, I just turn on the studio heater a few minutes before the kiln. Once I start work, I usually turn the heater off because as the make-up air comes in from outside, I'm just paying to heat the garden!

I’ve been using the kiln at least 4 times a week without any more problems. However, this morning, it got up to temperature OK but when I started to work (with fan going and window open for fresh make-up air), obviously the studio got cooler again. Then I noticed that the kiln was losing heat with alarming speed. It has been much colder outside earlier on in the week and last week and it was working fine then.

In fact DH said the car was registering minus 2 when he turned on the ignition and that's much warmer than the last couple of mornings!  So I've e-mailed Cherry Heaven again to ask them what they think is up, I guess either relays or the thermocoupler. No beadmaking for me until it's fixed. 

EDIT after initial posting: Quick phone call with Cherry Heaven chap - I have an exercise to do when it's cooled down and then ring him to let him know how the kiln behaves to diagnose exactly what replacement part(s) I need.