Knock/clunk from the rear..

Either way, I didn't get to try the boot lock as it has been raining and snowing here.

I really did think it was the exhaust popping when I picked it up but as I've listened closer, it doesn't seem that sort of noise. I guess it down to trial and error now.
 
just drive round with someone in the boot and they will be able to tell you hahaha it is the exhaust mine doest it
 
Mine definitely sounds like its the exhaust tail pipes knocking on the diffuser.

No too annoying yet - besides the car's under a foot of snow just now :rain:
 
Mine does it cold, it's definitely the exhaust/diffuser in my opinion. Five minutes of driving and it's gone so I'm none too bothered about it at present.