Pull the handbrake switch once and listen for the brake to apply and wait for the parking brake light to illuminate on the dashboard; it might take two seconds - not a millisecond. Then pull it again. Always leave the vehicle parked in gear anyway. If the dashboard light doesn't show then the brake is probably not applied. Never take it for granted that the brake is applied because the switch has been pulled. When parking on a sloping road park with the front wheels turned so that if the car rolls away the wheels are stopped by the kerb.
If the brake doesn't work you should not drive the vehicle. The parking brake requires maintenance, like all things and there are various posts on here giving instructions how to do it. If you can change a wheel you can probably adjust the parking brake.
It helps us all - and you - if you can edit your personal details to show the vehicle details on every post you make. Using a phone or tablet to view posts often gives a restricted view of this page unless the display setting are altered. View it on a PC or laptop (if you don't already) and you will see the difference!
2015 2.2 CDTi SENav 163ps manual 4x4 in Carbon Flash with 19\" alloy spare towing a Bailey Unicorn III Madrid @ 1500kg.