What precautions should I take to setup a home electronics lab? (Living in the UK)
You should read your insurance policy exclusions very carefully (even better, get a lawyer friend to interpret- they're good at finding worst-case interpretations). If you end up with a £100K lab it may not be covered. If you're planning on using cheap unapproved products that could cause a fire that may also be a concern, especially if they are mains powered or store enough energy to be a fire or other kind of hazard. 

As far as safety goes, isolation transformers to reduce shock hazard on mains-powered devices and auto-shutoff of the soldering iron are good. As extra protection, I power mine from a switched outlet so it definitely goes off when the lights are out. Also a proper solvent cabinet for storage of flammables such as solvents (eg. flux remover). If you have metal working equipment that throws sparks (grinders, welder, etc.)  there are additional concerns, as with storage and handling of compressed gas bottles.