Hi Lizzie
Do you mean "The other was the towing pack, at a slightly eye-watering £685. For that you get a detachable tow bar that, once attached and pushed out of view, can be revealed at the tug of a lever, accompanied by a piercing beep."
My Insignia is 18 months old and has a factory-fitted retractable tow bar which pushes out of view by means of a tug on a lever, hence the eye-watering money. Yes, the alarm is very piercing during its transition from securely stowed to securely open, and vice-versa. I wouldn't expect a detachable tow bar to be able to be pushed out of view, one would just detach it.