VAT Repayment

One of my client started business of export. Because of this Vat returns shows repayment. The case is with Assurance officer. We provided all the relevent information which he seeks and more than 30 days gone. I called him about the progress and he said that it will further take 2-3 weeks. As far my knowledge is concern HMRC must repay vat after 30 days from the date of submitting information. Ofcouse they pay 5% supliments payment if delay is more than 30days. But my question is is there any way to get back vat repayment as early as possible. Can we force them to pay?