The payment details page shows your billing address, and your VAT number. If you are outside of the UK, but within the European Community and have a VAT number, you can enter it here for non-VAT payments.
Additionally, if you wish to make ongoing payments less regularly, you can update your Billing Frequency. You can choose any number of months up to and including annual payments. If you don't want payment to be taken automatically at renewal, just disable the Attempt to take payment automatically? option.