Insulation of single cavity block wall

The house I live in is 5 years old. I was changing a vent somes months ago and noticed I have a 9" cavity block wall with insulation in loose plastic inside the plasterboard. That is it. Kildare County Council allowed this be passed 5 years ago. It would not come close with new Building Regs.

Can anybody tell me how I can improve the insulation for the walls without reduciing the size of my rooms.(replacing insulation with bigger insulation)

your only real option is to insulate externally.

This would be a big and expensive job however.

see:
[broken link removed]