EMONTH slow response

I've got an EMONTH that I would like to repurpose as a room central heating thermostat, I'll use openhab to do the work, but I need to speed up its response to temperature changes. Currently it lags behind my thermostat in response times.

My first thought is to run it from a power supply, increase the sampling rate and then see if I can install a small fan inside it to ensure a steady stream of airflow past the sensor. I'll also remove the battery mountings as that seems to stop most of the convection airflow within the case.

EDIT: I tested it with the lid off, and the sensor bent out so it was in unimpeded airflow, that gave excellent response times way better than the Ecobee, so its definitely airflow being restricted inside the case that gives the slow responses. Maybe relocating the battery carrier elsewhere, and putting the lid back on is all that's needed. The circuit board in my EMONTH has the battery tray mounted horizontally, so I've unscrewed it and placed the board back in the box rotated by 90 degrees so it matches the picture on the hardware page to see how it responds.

Can anyone suggest anything else that's worthwhile?