Hopefully i can help..
Is this from the front or the rear you hear this noise?
Have you ever hear it when moving forward or cornering even etc ?
Only have the noise when reversing, and it comes from the back
Hi.there thanks for getting back..
By the sounds of description anyway this will most likly reside at the rear brakes that maybe causing your problems.ie:- pads themselves dics or the brakes simply not releasing fully "calipers" etc or elec handbrake not fully releasing.you would usually know this if the one of the two or both are really hot or radiating alot of heat/brake smell - there was a recall regarding the rear mounting bolts on the rear for the caliper in which a small number of Peugeot 3008s because the tightening torque of the rear brake calliper mounting bolts could be incorrect. it led to the slackening of the bolt and an increase in noise during braking. So that could be something to bring with the dealer and see if your was effected or has been inc in that recall and wasnt aware of it..but by the sounds of it it does certainly seem to point to the rear brakes...i do hope this helps