There are two concession rates:

Rate 1 for those on pensions and full-time students - this is the medium fee.  This is also the rate for school children. (See "Can children enrol?" )
People on enhanced benefits (eg highest incapacity benefit) or receiving supplements to their earned income are considered as similar to those on pensions.

Rate 2 for those on basic benefits including unemployment benefits - this is the lowest fee.   

Proof of status must be produced.