Car alarm sound in boot, on continuously

[GaryStevens]

We have a 2014 model, there is a strange alarm sound that is on all the time, you can barely hear it from the outside, apart from if environment is very quiet. It's louder inside and changes pitch when driven.
No idea what it could be. Anyone?

 

[evman77]

We have a 2014 model, there is a strange alarm sound that is on all the time, you can barely hear it from the outside, apart from if environment is very quiet. It's louder inside and changes pitch when driven.
No idea what it could be. Anyone?

is the sound only when in D or R?

 

[AndyInOz]

Can you get someone to make a recording of the sound, and put it up on youtube for us to hear?

The only time I've ever heard a sound from the rear of my 2014 model is when the powered tail gate is in operation.

That's quite loud, and one long beep every two seconds (I think).