Take a look at: http://www.hmrc.gov.uk/vat/managing/reclaiming/partial-exemption.htm
If you only supply exempt goods such as:
insurance, finance and credit education and training fund raising events by charities subscriptions to membership organisations selling, leasing and letting of commercial land and buildings - but this exemption can be waived
The views expressed in this post are my own personal (HRA protected) views, and are not representative of any organisation I have any involvement with.
Welfare services that are provided by charities such as care homes are VAT exempt, however you must be a 'not for profit organization' in order to fall into this category. I would look on the HMRC website for further details