That's brilliant R0J0hound.
It makes a lot of sense just to maintain the hero position. I was rebuilding my approach from Flash which was object oriented so made sense for each character to keep it's own lists. Even in Flash this would have had benefits though in that there would only be a single data source.
Cheers, I was going to put Construct to the side for a while and see what developed but with the slow down issue solved for now I'll keep going with the port.