This is false. You're welcome to install whatever air-conditioning system you want, the only requirement is that it needs to be deployed by a certified installer. Which makes sense, of course, we wouldn't want DIY setups that can say leak toxic chemicals or cause electrical fires all over the place.
As you said, you are not allowed to install it hence it is forbidden for you, you need a professional to do it for you. It is 400€ to buy a unit, but if you ask an professional shit cost 2500€ at least. r32 aint toxic and it is only mildly flammable and a few 100 Gramms, meanwhile anyone can use their natural gas cooker in their house alongside a 11kg bottle. I don't see the electrical hazard if you plug a small unit into a normal power socket. They teach how to wire a plug in school in the UK.
There is a big difference between mandating products offered to the public need to meet basic safety norms and mandating that you obtain the services of a third party cartel to maintain your own property.
You are not, in the UK at least they teach you how to install a plug yourself in school. Please tell me what is the hazard of adding a plug to your aircon?
