You don't say what your friends disability is ,but it's impotant to remeber that just because someone has a disability doesn't mean they are covered by the act the wording is as follows
Subject to the provisions of Schedule 1, a person has a disability for the purposes of this Act if he has a physical or mental impairment which has a substantial and long-term adverse effect on his ability to carry out normal day-to-day activities.
This site explains it clearly
http://www.direct.gov.uk/en/DisabledPeople/Rig htsAndObligations/DisabilityRights/DG_4001068
You would need to prove that they were trating your friend differently because they were disabled.
Charges can be reclaimed just for the reason they are unjust -see here
http://thescotsman.scotsman.com/business.cfm?i d=587612007
As a physically disabled person myself I encounter prejudice from many sources including colleagues and even my employer so I do have sympathy My advice would be for your friend to find another bank