Hi Simon, It's not Knox but i have Forcefield Proshirt X-V.
XL/XXL if you're interested.
Theres a zip on one side of the chest plate. It has been worn a bit but it's in excellent condition. There is one stretched hole in the mesh on right shoulder which you can see in photo. This is the only imperfection I can find.
Ticket price says £219 you could have for £75 if you don't find the knox.