Doc (Hubby) says a big thank you to all of you who have taken the time to check out the links in this thread.
He wanted to say this personally but didn't wish to join a vegetable growing forum as he's not a gardener...he just cooks all the veg I grow! 
I've since removed all the plastic and this little house has become a great little shaded area for my water food garden. I've been growing Water Chestnuts, Arrowhead (Duck Potatoes) Watercress, Kang Kong and Lebanese Watercress all through the very hot summer we had this year.