There are definitely ways to cope with and adapt to partially heating your home, but having NO source of heating at all in a cold damp climate is unhealthy for humans and buildings.
Also, air temperature alone is not enough to decide how healthy or comfortable a space is. 18 degrees will feel cold in a damp and draughty house, whereas with the correct clothing 16 degrees can actually feel fairly comfortable in a house without damp or draughts.
I managed one winter in a big draughty house with two pre-school children and non-working CH. However, I had a working fireplace and a plug-in oil fired radiator which I used for 3 or 4 hours a day. It wasn't too bad, but that's because we had one room that was comfortably warm for most of the day and the ability to pre-heat rooms like the bathroom before bath time and the children's rooms before putting them to bed. I did things like using the hairdryer to quickly take the chill off bedding and the children's clothes in the morning and putting pyjamas in front of the fire before bedtime. We wore lots of layers and the children were allowed to come into my bed in the night if they woke cold. I'd go down at 6, get a cup of tea and get the fire going, then go back to bed with the children and read/watch cartoon on the laptop for an hour or so until the sitting room had warmed a bit.
During one particularly cold snap we 'camped' in the sitting room and I kept the fire going all night, but mostly it wasn't as bad as you might think.
Skip forward to now and I have full CH but will let the temperature drop inside the house when it's just me WFH. Hot water bottle under feet, oodie, fingerless gloves and frequent breaks for hot drinks and movement. Keeping the door of my tiny office closed helps keep in the heat generated by my body and computer.
HOWEVER THESE SITUATIONS ARE IN NO WAY COMPARABLE TO LIVING WITHOUT HEATING. In both situations there were either rooms that were warm for most of the day or times of day when the house was normally heated. The air was not damp.
We will definitely cut back on our oil CH and our electricity use this winter, but I would cut back on food before I considered not heating our home at all. Unfortunately in our case this will mean keeping our wood burner going (something I've previously tried to avoid using too much from an environmental/health perspective) I feel very grateful that we can afford to get away with this, I know others will not be in so fortunate a position.