As for the 'What is a bedroom/bedroom size' issue, we have taken legal advice and the number of bedrooms in a property is as stated in the tenancy agreement.

Where in the Act does it allow for the opinion of a third party to dictate the amount of benefit that a person should receive?

Whether a room is, or is not a bedroom is a matter for the local authority to demonstrate and between them and the tenant.

The laws regarding bedroom size were brought in to prevent unscrupulous private landlords overcrowding properties

But obviously not to prevent governments from doing so in a non direct way.