GreatauntieLinda Care Allowance is complicated. Retired people do not qualify for the cash payment because it is there, essentially, to compensate those, who could work but cannot because of their care responsibilities. As you are not earning and already have a payment from the state, you cannot have both. That is an explanation -not- a defence.
However, if you qualify for a Carers Allowance, in that you meet the caring qualifications for CA, but cannot receive the money because you are in receipt of a pension, there is still a way you can benefit from it.
Those receiving a state pension who qualify on care grounds for CA can claim a supplement to their Pension Credit, or possibly, if your income is currently just above Pension Credit, even qualify for Pension Credit, with all its benefits.
So I suggest you speak to your local branch of Age UK or local Citizen's Advice Bureau to find out whether you qualify or not.
Here is a reference to the Age UK Fact Sheet on Carers Allowance. Go down to page 9 and you will get the information you require there.
www.ageuk.org.uk/Documents/EN-GB/Factsheets/FS55_Carer's_Allowance_fcs.pdf?dtrk=true