Floor insulation - recommendations please

Any recommendations for underfloor insulation (non toxic/ no foam) for suspended timber floors?

I've got one quote which looks solid, however I'm keen for another, plus also keen to hear about materials you have had installed (hemp/ wood fibre etc). DiY is cheap but a necessary ventilation membrane doesn't seem fun for DiY.

Presumably it's important to get electrics (socket wires) checked first before they get buried in insulation?

Tips/ installers/ trade bodies to know about welcome.

Seems like relatively few people have had this done locally (please prove me wrong)... but a lot of heat is lost through old draughty floorboards.

Thanks in advance!