The idea is to make this in two halves (ie cut along the net) which can be removed easily to recreate a dining room at will; I was going to attach lipping underneath around the edge to bear against the edge of the dining table, to hold it in place. Top will be in 12mm thick board I think (compromise between weight/durability/ball bounceability).
So, the question: what sort of board would I be best using? In real money, we're talking two sheets approx 4'x3'. I'm thinking ply or MDF: which would be best in terms of resistance to warping, given that it will be used in a CH house and probably stored vertically in a garage when not in use?