Difficult to give a crash course in alarms/immobilisers as its a big subject but I will try to give a few pointers below.
The Mk2 Golf didn't come with an immobiliser as standard, it wasn't a UK requirement at that time. If you don't have an alarm and you don't have a touch key or a transponder on your key ring, it hasn't got one. The simple answer is if you don't know whether it has one or not it probably hasn't.
For insurance purposes what you require is a Thatcham approved alarm or immobiliser that has been installed by a VSIB approved installer - the alarm will have an immobiliser built in. When this has been fitted the installer will issue you with a VSIB certificate. The insurer will want to see this for sure if you make a claim, especially for theft so don't bother lying about it otherwise your insurance will be invalid. Many insurance companies will not insure a GTI unless it has a Thatcham approved alarm.
Look at
www.vsib.co.uk to find an approved installer in your area. Best to go for an alarm but if you can only afford an immobiliser go for the transponder variety. NB? It has to be a Thatcham approved alarm/immobiliser. Tell the installer that it is for insurance purposes.
