ff5f1d46_ons___Adur___Worthing_Councils_Exemption_Classes_Definition
[Class] Class W [Definition] 
An annex (which is separately banded) that forms part of the main accommodation consisting of a single property with two or more dwellings, where the annex is occupied by a dependent relative of the resident of the main dwelling. A dependent relative is someone aged 65 or over, severely mentally impaired or substantially and permanently disabled. This exemption may apply to occupied granny annexes.
Discounts and exemptions - Adur & Worthing Councils