Microsoft InTune Certificate not showing in Push Certificates Portal

Hi There - We have used InTune for nearly a year to administer the mobile devices in the company and its very good.

I have just gone to renew the MDM push certificate between InTune and Apple, and have found a problem. I have downloaded the CSR file - so far so good, and then logged into Apple - and found that the certificate is not in there. My email address is referenced in InTune - and that's the same email address I used to log into Apple with, (and the same email address an Apple ID that I created the original certificate with) but the certificate is not in there.

I could of course create a new certificate - but I am pretty sure that will knock all the apple devices out of InTune

Does anyone know how to renew the certificate - if it is not in the push cert portal?

Any help would be much appreciated