You cannot revalidate an SEP rating without a JAR medical.
You can get an SSEA rating on your PPL before the SEP expires - it effectively replaces the SEP, will expire on the same date but will be revalidated by NPPL criteria.
You can apply for an SSEA rating after the SEP expires, but you will have to do the SSEA General Skills Test.
edit: actually, you can revalidate the SEP if you held a valid JAR medical within the 12 months prior to your rating revalidation, but this loophole is supposed to cater only for temporary loss of medical.
Last edited by B4aeros; 8th July 2011 at 18:43.