The manufacturer usually puts in the installation manual a minimum length for the pipes, which is usually 3 meters, so your technician was probably right
The condenser or outdoor unit will transfer the heat from room to wherever you put it. Putting in a room will heat the room it’s in and then make the whole system very inefficient and ineffective.
Considering the last job I followed a plumbers installation, who pressure tested by filling the system with water checking for leaks! Ruined the system total new installation needed. Soldered joints and plumbing installed insulation on the interconnecting pipes. Trust me there are a lot who state they can install and I agree any monkey can hang 2 units connect 2 pipes and fit an interconnecting cable. This doesn’t mean it’s actually fitted to a decent standard so yes F Gas certification pretty much should demonstrate some competence. I mean god help if a refrigeration engineer installed a boiler ! Which I’d never dream of considering. Horses for courses. Also you’re entitled to your opinion or comments 👍🏻 keep up the good work 🙄