I despair of Examiners who are so slack with their paperwork!
The Examiner is
required in your case to:
Complete the 'Ratings - Certificate of Revalidation' page in your licence for both your SEP Class Rating and IMC revalidations.
Complete Section 4 (Examiner's Certificate) of SRG\1119, which is the form you then send off to the CAA.
You completed your requirements in good faith and had your licence signed up before the expiry of your ratings. So you're fine - all you need to do is to download a SRG\1119 from the CAA website, fill out your details correctly, get the Examiner to complete section 4 and you then send it off to the CAA. The Examiner is also required to keep records, so proving your dates shouldn't be a problem.
Oh - and tell him he's an idle git who needs to stop messing his customers around with slack admin! (I say 'he' not because I don't think that there are lady Examiners, but because all the lady Examiners I've met are meticulous with their paperwork. So it must be a 'he'!)