HB bedroom tax - pre-1996 protection

Could anyone confirm whether my client (council tenant) qualifies for exemption from the bedroom tax for the 1/4/2013 to 3/4/14 period. She has been in the property continuously and has been in receipt of HB for the period. CPAG page 397 state that she would not apply unless her rent had been restricted or council considered her property too large / rent too high. Thanks.

May be worth asking the LA to make a revision for the period in question.
As long as there is evidence to support it its worth giving a shot