Haha sorry for confusing you guys, i deffinately still have the stock bov!
when purchasing the car i got an raa check and the raa mechanic said it has an exhaust bov fitted, and my mechanic also said it has a exhaust bov but never actually asked him where its located.
The noise deffinately comes from the engine bay on deceleration though just as a bov would just not sure where it is, might record the sound and pic of engine bay/video to show you guys.
Im as puzzled as you guys are but i looked in my rear muffler and theres deffinately nothing around there!