(b) Revalidation
Examinations and/or assessments for the revalidation of a medical certificate may be undertaken up to 45 days prior to the expiry date of the medical certificate.
(c) Renewal
(1) If the holder of a medical certificate does not comply with (b), a renewal examination and/or assessment shall be required.
(EASA MED A.045)
So there is no legal obstruction preventing you renewing it even before 45 days within expiry.
Last edited by Dufo; 26th Oct 2012 at 14:27.