The biggest threat to increased premiums in recent years has been the increasing levels of thefts. Vehicle security and lifestyle of the proposer helps the broker or intermediary to understand the risk. The higher the value of your car, say £20,000 plus, the more likely you are to be asked to fit some security – e.g. one of the Tracker systems probably being the most appropriate – particularly if you live in a metropolitan area.
The trauma of losing a treasured possession has to be worse than parting with a cheque for an appropriate deterrent! Also, do the obvious. Put your car away in the garage and lock it up when you are at home. Insurers are not impressed when they learn your car was stolen from outside your front door when you have got a perfectly good garage. If for no other reason, premiums are often lower for cars which are habitually garaged.