9904 Registration of trades people

I am wondering if anyone can tell me how i can check up to see if a particular trades people are registered in their chosen field?
i.e. gas, in the uk you could check with corgi.
I am just worried that some of my friends have got in non legal trades people and they are planning to rent out the property, and i believe unless the trades person is registered they won't be able to recieve a certificate to say the job is safe. I know a new law came in. If anyone has any answers for me that would be great

Thanks in advance

Category
Building/Renovation

If it's a new install the gas company won't turn on if the installer isn't on the list with the right paperwork.

Here in Marche we have a service contract with an excellent company, both boilers are serviced every year, the company phones beforehand to remind us when it is due, and the appointment is always kept on time, also call outs are free under the sevice agreement. It gives us peace of mind, especially as I understand spot checks can be made. If anyone is interested plse pm me.
A