You can indeed claim the audit exemption, but only if your annual return (B1) and accounts are filed on time. If these are overdue at all, you cannot claim the audit exemption, and must have the accounts audited.
Also, just a minor point for anyone else checking this out, A lot of people are not aware that as a limited company, regardless of whether you are trading or not, you are still obliged to file an annual return and accounts with the Companies Office annually.
Many people assume that if they have a limited company that's not trading, they have no filing obligations with CRO, but this is not true.... i learned the hard way!!