If your friends damage something while helping you to move, their liability will be limited as they were acting out of courtesy by helping you. In this case your friends' liability insurance will likely only cover a portion of the damages. If you make use of a removal company, you should look at their general terms and conditions (GT&Cs) before entering into an agreement. Take a look at the amount for which the removal company is liable, because they may limit their liability. Find out whether there are certain damages they cannot be held liable for. In any case, it is worth taking out special transport insurance.