I have just started on the program and find no real problem sticking to 800 cal’s per day. My question is if I burn, let’s say 800 cal’s per day undertaking exercise does my daily calorie alawance increase or remain static.

Morning, I would listen to your body, if your not hungry then stick to the 800 cals. But maybe if you have pushed yourself doing exercise a few more would probably be ok. But maybe you should ask Michael on Twitter.
Good luck