When braking and coming to a stop there is creak from the back end of the car. The brakes have recently been changed but it was doing this before so i don't think it is brake related. It is more often happening when braking from slow speeds. Car is 2013 model with 30000 miles on the clock.

 

My last car was a 96 XJ6 Sovereign, which I drove for about 6 years. I recently changed to a 09 3.0D XF and notice more in the way of little squeaks, clicks etc. in the XF. The build quality is noticeably different in both cars, with the XJ6 being superior IMHO. I imagine the noise you hear is just suspension components/bushes squeaking under pressure. If you get someone to brake slowly, as described, while you stand outside listening, at the rear and at both sides, you might be able to pinpoint the location.
Alternatively, chock up the rear of the car, spin the wheels in turn, by hand and get someone to apply the brakes. This will remove the suspension somewhat from the equation and you can possibly localise the source of the sound more accurately.

Bushes dry out and harden with age and can squeak when put under strain or pressure.