That is ia really good question - how did non-UK voters vote, especially the Irish. I have been doing some digging with little success. I found this link -
https://www.qub.ac.uk/brexit/Brexitf...,728121,en.pdf on voting patterns in orthern Ireland but that is more identity than where people were born. 87% of people who identify themselves as Irish voted Remain in that study.
There's the Ashcroft polls as shown here -
http://researchbriefings.files.parli...9/CBP-7639.pdf for all non-UK born voters. The data is on page 22 (for statistics fans, the R2 value was 0.35 so not a hugely strong correlation)