I genuinely didn't realize that they had more then 1 page. I thought their biggist was 20x40! I didn't even bother looking for page numbers!

I can get away with using 6"x3/8"x... it's £15 for 1000mm so it should be more then enough. any metal above this size gets very expensive very fast!

I'm going to have to file the supports for the rail to allow the screw supports to be placed. I can live with that.