Thanks THECORBYLOON, think I understand the issue now.
There are premiums for people with a disability, although it would be better to call them allowances because the claimant doesn't actually get paid these sums.
Someone on benefits would normally get full Housing Benefit for their rent. They would also get full Council Tax Benefit.
Someone who has a disability, such as blindness, who is working would have the premiums applied to their total rent. This means they would receive more HB and CTB than someone without a disability on the same wages.
Does that make sense?