I work for a small contractor and we have an ongoing problem with a customer who has queried the VAT we have charged because it is a listed building etc. We as anniebird has suggested went straight to Revenue and Customs and asked their advise, which was, its up to the supplier to decide on the amount of VAT to be charged, they cannot and will not give a decision. Your customer, however, should have a certificate from Revenue and Customs saying that they can have a lower rate VAT or zero rated VAT charged.