You have completed in excess of one hour with an instructor in the requisite period. The instructor has signed off the Difference so an Examiner knows the flight is genuine and flown with an instructor therefore it qualifies. The licence can be signed by an examiner free of charge and will run for 24 months from the current validity date irrespective of when he signs it. Don't delay. If it goes beyond the date, it expires and you will need a test to renew it.
if I were to find that Examiner now to check my logbook, the SEP would run from July 2011
This can never happen, the two scenarios are Revalidation which occurs within the period of validity and Renewal which occurs outside the period of validity. The date can only change for a Renewal which requires a test and cannot occur as a result of Experience!