Many would expect sprinklers in a domestic situation to be overkill unless there was a very specific need. I tend to agree.
Good fire prevention and early warning is most likely the better solution. Alarms, ensuring the electrics are all safe etc. Extinguisher on hand.
If you wanted that extra bit of protection. These could be a neat solution.
https://simplyextinguishers.co.uk/automatic-extinguishers/
Self contained, cheap, and can be placed in an area of concern. They may be an ideal solution if you want to be over cautious.
I also remember reading, somewhere sometime, that mains fed sprinkler systems have to have ongoing maintenance due to the water stagnating in the pipes, as there is the chance of legionnaires developing. Although the risks may be low. It's something to check-up on (I may be wrong on this last point, as I can't remember where I saw it.)