I am involved in carers support services and Direct Payments are a constant source of confusion! Firstly there appears to be no set rules for how the monies can be spent, each local authority sets it own guidelines. Even within local authorities there can be disagreement with one dept saying you can do this and another saying you can’t.
Another thing that has happened with some of our carers is that they have been subject to employment rules as they are directly employing personal assistants, this brings in such things like sick pay and pensions etc.
There were plans to combine Health and Social Care Direct payments, but i have lost track of what is happening there see https://www.england.nhs.uk/ipc/what-is-integrated-personal-commissioning-ipc/
I have heard of people challenging authorities about transport and what is important to the individual, but this has taken a lot of effort. Check if you have a Carers Support Service in your area or a People First organisation.
Hope you succeed