I would fear that no amount of tweaking with Naim frame is going to get your room to sound like you wanted to as it would appear you have a conservatory behind the speakers and a lot of glass.
Before expending all this money what I would recommend in particular if you have a spare computer is to get a Roon and do sound measurements with the home audio fidelity program and get a set of filters that will attempt to sort out your room – Thierry is very good if he cannot manage filters that will improve the sound he will let you know.
We are living in an era where electronically you can indeed change the room!
.sjb