30If a service is generally provided only for persons who share a protected characteristic, a person (A) who normally provides the service for persons who share that characteristic does not contravene section 29(1) or (2)—
(a)by insisting on providing the service in the way A normally provides it, or
(b)if A reasonably thinks it is impracticable to provide the service to persons who do not share that characteristic, by refusing to provide the service.