Cheers Neil.
My new harnesses didn't come with any fittings for the straps to be mounted in the rear. I'll be fitting them to a cage when I get one sorted, but I want to replace my current harnesses for the time being. Don't want to take the clips off my current harnesses as a potential future buyer would probably want them!
With regards to how they're fitted, you can 'thread' the straps through the slots in the 'spring clips' and secure them like that, in the same way you would with a cage. If that makes sense... lol
Think I'm sorted now, cheers for the replies guys