Hi Michael Welcome to the forum
I am not sure where in the UK you are but I am in Kent and I too do most of my smoking overnight. This includes a lot of cheese. The temperatures here are usually fine overnight and it does not annoy the neighbours. I have found that recently some nights are too cold so I built a thermostatically controlled heater to keep the smoking chamber at 10-12 C.
I live in Lincolnshire, so I get it a little chillier up here.
I found over the past 2 weeks when the temp has drop below 0°C my smoke grill seems to take a little longer to go through so I chucked it in my wood shed, and it picked up again.
What set up are you useing (if you don't mind me asking) to smoke?