If you have brought one of your buy-to-let properties with another party (perhaps a family member). There could be tax advantages of joint ownership but it is possible to allocate the rental income in specified proportions. For instance, you may have a student daughter who needs additional cash to see her through college. It may be tax efficient for your daughter to receive most of the rent, rather than you have to pay tax on it first. Have a look here for the full details.
Landlord insurance - professional rates