Mac User Group has been informed that unless mains-attached equipment used by the group or by presenters has undergone compulsory 12-monthly electrical testing & tagging for safe usage, it will not be permitted to be connected. Thus far, it only applies to the main monthly meeting. In my case that would be the charger for the MacBook Air.
I'd be able to manage without that, the Mac has good battery life & can also be run/charged from a thing called a ChugPlug
The Men's Shed has their own internal Test & Tag equipment & personnel but due to insurance issues, can't test & tag for use outside the shed environment.
After costs, it's not financially viable for someone set up as an electrical safety test & tagger to charge less than $15 per item tested.