After evaluating the work coming out of the first firing I realise I will need to change a few things before the next firing. Firstly, I need to address the unevenness of the heat in the chamber. After doing some more research on kilns of similar design, the key areas seem to be:
*adding a bag wall inside the kiln to deflect the heat upwards
*pack the work in the kiln 'tighter' by packing more work in
*adjusting the firing cycle
It is definitely a learning experience.