Absolutely right - but not illegal unless accepting payment or a landlord.
Ring-Ring
Ring-Ring
"Hello Mr RGI person, please come to my house and conduct a safety inspection on my heating system - I'll pay the usual rate."
Landlords are obliged to do this anually, by law - there is no restriction that prevents a private person doing the same - in fact the HSE rcommend that people do this.
So there...
Peccavi, July 2009