Last night I bubble wrapped the composter to prevent heat loss from the side walls:
At 07:00 this morning the air temperature at 7.5 deg. C which was similar to the previous day. However, the temperature around the seed trays in the box was 15.5 deg. C. The next milestone is to see what germinates, the trays contain approximately 10 seeds of cucumber, Cayenne chillies, California Wonder peppers and broccoli.
There should be a comment on the errors associated with temperature measurement, suffice to say that I stood in such a way, that the thermistor was in shadow and far enough away for it to not sense the warmth in my body