Thanks for the replies guys, it is as you pointed out an overlap, I bought the suit used and pretty much every join has been done with velcro so too much work for converting, this will be used maybe for occasional fancy dress and for the most part will just live on a mannequin. I'm on a very tight budget at the moment and just bought what I could afford for now, if I decide to join properly at some point I'll be saving for better armour. I think the best way for me to repair this is just glue from behind and maybe some liquid abs down the front to fill the crack. It actually split on the journey home from picking it up, I think due it being already cracked with age which unfortunately I hadn't noticed, the other thigh also has a crack but hasnt split apart yet.