Update 1st April 2011:

The bus pass provides the pass holder with free off peak travel on registered local bus services anywhere in England, between the hours of 9.30 am and 11 pm Monday to Friday and all day at weekends and bank holidays. Additionally, the Wiltshire Bus Pass also allows free travel at any time on buses in Wiltshire, but there are some bus routes in Wiltshire on which the pass is not accepted before 09.00am.

See Here

Bath and North Somerset - See Here

Goucestershire inc. Bristol - See Here