Thinking about it, i dont know if craigs S4 has one either.
I've had the battery out of that to clear the scuttle drains, and dont recall seeing it...
Olly: if it was there, you'd see the brackets, as they're part of the shell on A4/S4's that had it from the factory...
I wonder if its a facelift feature? They defo tweaked around with the suspension going to facelift, i wonder if this was one of the additions?