Insurance & local authority rules on multiple occupancy

[Ian-and-Jo0]

1. I am about to start hosting and in preparation contacted my insurance company only to be told that my current house/contents insurance would not be valid if we rent through Airbnb. Has anyone had this experience and any ideas on companies to contact
2. As we have three storeys our local watford authority is suggesting we need a multiple occupancy licence at considerable cost. Apparently this cuts in for 5 or more people or two plus families. Has anybody come across this and again any help or advice would be welcome.