We have one sheet of 12cm thick insulation - it measures 240cm x 62.5cm and it's in fairly good condition.
It has broken in one place but is still intact via the silver lining on the outside so could be installed flat. At one end, it is slightly cut away which you can see in one of the pictures.
Sheet of 12cm thick insulation (Stroud GL2)
This offer has been gifted to someone and is no longer available.