Whenever i do a three point turn and then drive off ( usually in the morning when i am leaving to go to work ) - a few seconds later there is a single 'ping' type sound coming from the rear of the car .
The sound is like the sound you hear when the spring in a bed mattress
' pings '
found this on the internet for you
The ping is probably a binding upper strut mount. That has to get really bad before it becomes a safety issue. I've never seen one so bad that you can't steer the car but it could prevent the steering wheel from coming back to center on its own after you turn a corner. Long before that you would notice an irritating need to constantly make little corrections. Most of the time all you will notice is the noise.
"....When reverse gear is engaged the PD1 Vision rear parking sensor provides an instant, automatic, self-diagnostic function that maps out the surrounding area of your rear bumper constantly monitoring this as you reverse with 100% accuracy, providing you with 3 different audible tones and visual LED's (Zones) alerting you of your proximity to surrounding objects...."
If the rear brakes are drum type, it's likely to be a brake return spring pinging as the brake shoes re-align themselves when changing from reverse to forwards.