Refund timing for duty exemption: cheque must be issued before sanction; claim must be filed within six months of payment. Manufacturers entitled to a further duty exemption when a saloon car is registered as a taxi must refund the exemption amount to the purchaser and file a statutory refund claim. The Board interprets refund as receipt of the cheque by the purchaser, but the refund claim period runs from the date of duty payment; therefore the cheque must have been issued before the claim can be sanctioned, while the claim itself must be filed within the statutory filing period from duty payment.