Letter of offer extension question

We have a letter of offer with AIB for 6 months up until the middle of February for a new build. How likely is it to get an extension on this without having to submit all the paperwork again? My wife is a civil servant and is currently out on paid mat leave. The paid leave finishes the end of January and we would like for her to take up the option of 16 weeks unpaid leave. We are using the option of no repayments for the first 6 months of the mortgage as she won’t be earning at the start, to help us get by.



If the build runs over and the loan offer expires, are we able to get an extension? How will the bank look on the unpaid leave? Is it best she returns to work to help get the mortgage even though her being at home with the kids for the extra bit of time will be invaluable in time.



Thanks