Hiya
The places i have asked get paid themselves for selling the cardboard so cant help.
For more info on the charity , please have a look at
SOS - Support Our Soldiers. We are a non political charity that supports the troops, mainly whilst in operations abroad but do work here as well, especially with BLESMA (British Limbless Ex Servicemens Association).
Please feel free to pm me if you want to know more
Thanks xx