Insulating exterior wall under weatherboard

[psimsy]

I am refurbishing the weatherboard on the front of my 1960's house and was hoping to put some insulation under it. The construction is brick with batten and the boarding is applied. Sadly there is no cavity in the brickwork.

I called Kingspan helpline and they said i would need 60mm of foam to get it up to building regs u value. I don't have space for this so was wondering if i could use Triso Super 10 or SuperQuilt the multi-layer material that would save loads of space.

Does anyone have any experience of using a quilted insulation on an exterior wall?