@ robsters, you can send an email to this email address:
eutreatyrights@justice.ie and address it to the name of the person in the letter requesting for these additional document, explain your situation and ask for additional days to be able to provide the requseted documents. Please always quote your application reference number, GNIB number, department of justice number if applicable, your full home address and your full name in the email otherwise you won't get a response. I did that about 6 years ago and i was given an extended grace to submit the document.