Whopity,
As you say, an examiner can revalidate or renew a SEP(L) class rating if the pilot's JAA-PPL(A) has expired, they cannot however exercise the privileges until their licence has been renewed.
All the relevant expiry dates are required on the SRG1119.
Don't think there is anywhere on SRG 1119 for the examiner to enter the licence expiry date, although might be a good idea if it was.