Pink, yellow and blue foam board in the US is a rigid closed cell foam (XPS - extruded Polystyrene) used as insulation in homes, it is a favourite of modellers because it carves well.
(Images) I've never found a local equivalent.
If you can, find a supply of EPE (expanded polyethylene) as it is an excellent shock absorber, it springs back to its original shape and size after being crushed.
(Images) You may have seen this stuff used in packaging TV's and whitegoods.
Styrofoam(EPS - expanded Polystyrene) is the stuff made of balls and when crushed will break apart/crumble and never recovers, not ideal.