Cheers for the replies. I had considered the plastic fluted slat material (correx), but unfortunately alongside match damage we've got a couple of scrotes in the village that may damage them (our covers got slashed last year)
The plan was to have sheet that is put and taken every game, but I know the hassle of this as it's always the same people that have to do it!
Thanks for the link
@Ayrtek. I hadn't considered standard tarpaulin. Ive just checked our measurements and think with a bit of work we can use a standard size which is a fraction of the cost of a custom one.
I'm now considering ordering a few and fixing them permanently. If they damaged we can replace with minimal cost.