Quote from VAT 700-01:
"If at the end of any month the value of your taxable supplies for the last 12 months has gone over the registration threshold, but you can provide evidence and explain why the value of your sales will not go over the deregistration threshold in the next 12 months, then you may not have to register unless you are required to do so because of the level of your distance sales or acquisitions. This is called exemption from registration."
Your problem may be that your sales for the second year fell between the registration and deregistration limits, otherwise you could argue that you knew that your turnover would be below the threshold and the above exemption applied.
John Perry
Central Business Services
Loughborough
www.centralbusiness.co.uk