According to Chapter 23 of the Value Added Tax Act 1994, the following is exempt from Value Added Tax.

'The supply to a handicapped person for domestic or his personal use, or to a charity for making available to handicapped persons by sale or otherwise, for domestic or their personal use, of...equipment and appliances designed solely for use by a handicapped person; parts and accessories designed solely for use in or with goods described above.'

A handicapped person is described as 'chronically sick or disabled'.

The complete document can be viewed here

VAT Exemption Form