i think there just holes.. they may have been used as acces ports while making the golf....in factory.
ive never heard of additional locks on the door...
if people are going to bend the door back then you may need to be thinking of upgrading your alarm to external perimeter sensor.....depending on if you have an alarm and what make it is they sometimes do add ons so you can upgrade your alarm to this... if you dont have an alarm clifford do theses but they are expensive..... the next best thing would be
microscan.
i'm getting one of theses myself theses dont sound cheapo they have a crystal clear voice . i lad who i know had a rs turbo it had one of theses on and when he pulled outside his dads house across the road he was playing with it and my mate heard it and was well impressed he thought it was a clifford (my mate said oh you need something like that on one of thos) when i saw him i asked him what it was and he said microscan ..... very good quality. you can also buy theses from motorworld
www.motor-world.co.ukhttp://www.microscanalarms.co.uk/The Microscan AN300 Series incorporates all the features of the AN200 series by ACTIVELY protecting your vehicle and contents before a break-in using a choice of two-stage shock sensors or dual zone microwave technology. These compact alarms come with a 120dB siren and in addition to this the AN300 series comes as standard with a voice!
The Talking Car Alarm!
With the AN300 series you have voice confirmation of arming and disarming as well as a voice warn away system. The system will confirm it is alarms with a "System Armed" message and disarmed with "System Disarmed". If an attempt is made to break into your vehicle and the two stage shock sensor is activated (or approaches the perimeter of the car on the AN314 model) the alarm will produce a warn away message "Protected by Security System, Please Stand Back".