The first thing to do is to contact your lender and they should offer to reschedule your mortgage. Switching it to interest only for a while should free up a fair bit for you, even if you have 23 years left.
I have been in regular contact with PTSB and have had a payment holiday, went interest only for 6 months as well but need to look at something longer term which was why I was wondering about Deferred interest and Split Mortgages or would extending the length of the Mortgage make more sense.
Whatever option I pick I need to make sure it is the right one