Are you talking about direct payments for respite? If you are its when your given an amount of money to pay someone to do the respite for you as oppossed to SS providing a carer. The amount awarded depends on all sorts of things.
I know lots of people don't like having them as you become the 'employer' of the carer but many like them as they chose who they get as carer.
I also know some carers don't like being paid this way as they are classed as self employed, whereas others are F.T self employed carers.
You can apply to social services for a disabled child assessment and a carers assessment. Contact a Family have info leaflet. Many councils only awarding help for critical or substantial needs at the moment (eg your family at risk if you don't get it). However was a short break duty came in 1 April 2011. Will depend if they think you need a break from caring or your child has high level needs (here its only for very very disabled children or challenging behaviour).
However we get 2 hours per week to spend time with our other children (before the cuts hit) without DS who cannot tolerate / join in many typical activities. We also just got accepted into a monthly sitters service (run by a voluntary group but funded by social services) and the kids have been offered some sibling activities in the summer.
Have to be very careful now about operating DP - we have been warned off treating anyone as self employed as Inland Revenue apparently making lots of decisions that parents are the employer even if the carer says they are self employed. So it is safer to pay them net of tax / NI. Most social services will top up the DP to cover the cost of a payroll company so a firm will sort all the tax / NI out for you. Our works out at £7.50 gross for the carer. You can also use agencies that social services pay direct.
They will ask lots of questions about family support etc if they think you have any family within 50 miles you probably won't get anything. You have to make out you are desperate - about to divorce or something and have a very clear plan of what you need. Council funded respite homes eg an overnight stay at weekends tend to be for very challenging ASD children only around here.