There are limits for new sellers. If that is relevant to you there's a link to request a limit increase on here:
http://pages.ebay.co.uk/help/sell/sellinglimits.html
Also make sure you've added a bank account to your ebay account in order to transfer payments. Details here:
https://www.ebay.co.uk/help/selling/fees-credits-invoices/updating-your-bank-account-details?id=4796
