Thanks for the ideas and the comments, I am greatful for the willingness to share knoledge. I had an idea that I could run techscrews into the steel box section to attach a block with which to attach the form. The sort that drill, and cut their own thread. I have a 1/2 box of them left over. The side to side movement might be a bit of a worry. Looks like I need to do some more scrounging ( NZ for sourcing material for minimal cost) Thanks Don