Well, you could go through the hassle of conatcting revenue and advising them of this ...
..or just include in next years return which is so much easier.
You don't have to show the workings to Revenue except in the rare chance they ask for them. And even then if you have been honest and include a genuine expence a year later than incurred Revenue won't mind.
Over thirty eyars of both my company's business accounts and on my personal rental income accounts I have often incldued a bill from a previous year. Never had a problem.
I may be technically wrong but Revenue don't penalise people who are genuine ,honest ,keep good records but occassionally include a cost from a previous year.