If your car is not parked at your home address overnight, this will ring a bell and flash a red light at the insurance company offices. They will want to know why.
It could be that just down the road your friend has a convenient driveway, whilst you have not got one, meaning that if the car was parked at your home it would have to be left by the roadside. This would not good because it could then be a target for thieves or vandals. It could make common sense for it to be on a driveway; at least it would be safer from some passing moron who takes pleasure out of scratching a coin down the side of someone else's car. However, it could also be because the real main driver of the car is not you, but your friend. If this is the case a common suspicion, amongst insurers, for this happening is because the friend has a bad driving record and would find difficulty getting insurance at a reasonable price.
It may be that this had never crossed your mind. It will certainly have crossed the mind of the insurance company's loss adjuster. If true it could constitute fraud, which is a criminal offence.
When you fill in an insurance proposal form one of the questions always asks where the car is kept overnight. It is imperative that this is answered correctly and truthfully because if it is not the insurance could be voided. This could lead to all sorts of unpleasant consequences, such as a charge of driving without insurance or an unpaid claim.
If indeed there is a good reason why your car will be parked other than next to your own home it is essential that you provide the insurance company with this, and highly advisable that you do so in writing. It is possible that your premium will increase as a result; but if you live on a major roadway and have no access to nearby parking your insurer may be sympathetic. The attitude towards this will vary from one insurer to another.
If you genuinely need to park your car elsewhere then a chat over the phone with a qualified broker may save you a great deal of money.