From the Royal Mail website of 31st Jan 2023:
Summary of International services which have been reinstated:
- International Tracked
- International Tracked & Signed
- International Signed
- International Untracked (Standard / Economy) Letter services
- Customers in Northern Ireland are also able to submit both export letters and export parcels for all services bound for Ireland into the Royal Mail network through all channels. These services are currently only available for customers based in Northern Ireland.
Delivery of International items may take slightly longer than usual and customers using Tracked services may notice different tracking information as items leave the UK.