You must not stop charging VAT until you are given permission to do so by the VAT office. You need to apply to deregister for VAT on form VAT7, and send the completed form to the VAT deregistration office in Grimsby. You must continue to charge VAT on your sales until your application to deregister from VAT is accepted, and this has been confirmed by the VAT office.
If you would like any further information, please do not hesitate to contact Southside Accountants Wimbledon & London.