Currently, moving data from QuickBooks Online (QBO) UK to an Irish company isn't supported as a direct or automated process. Each regional version is designed to meet local tax and regulatory requirements, so the system doesn’t allow transferring data between regions.
What you can do is export certain lists and reports from your UK company and bring some of that information into the new company.
You also mentioned third-party migration tools. Some apps can help move transactional data, but most only support migrations within the same region. Cross-region migration options are limited, so it’s best to confirm directly with the provider whether this is supported.
If you have any questions whilst working through the export or setting up your new account, feel free to reach out. I’m here to help.