Thanks for all the posts

Bit worried about the fella - with knowledge of decaying bodies :-)

To answer some of the questions them, its quite cramped down there and
musty. If the floor doesn't breathe - it will end up stinking like any
textile I've stored down there even in plastic bags. It does get some
ventilation but not enough.

I don't want the dirt and hasle of laying concrete as access is only
through the house. Should have done this before I did teh house up.
Stupid!!

But the extending the mat idea to a long role of perforated "grid
like" will give me acess to all the cellar and I can store stuff on it
so it doesn't get damp.

Its just finding the right material