Factual error: Northern Irish characters speaking to other Northern Irish characters refer to cellphones or cells. They're always known as mobile phones or mobiles in the British Isles. Nobody would use the American term.
Lochan Mor - S3-E8
Factual error: The credits refer to a 'PSNI lieutenant'. The Police Service of Northern Ireland uses standard British police ranks. He would be an inspector.
Lochan Mor - S3-E8
Factual error: Having crossed on the ferry from Stranraer to Northern Ireland, the Sons have a long ride through the Northern Irish countryside before reaching Belfast. However, the ferry from Stranraer docks at Belfast. They wouldn't be going anywhere near the countryside.
Factual error: When Tara goes into her office there's dried blood on the carpet from her faked miscarriage. Considering it's a bio hazard that happened days ago it would've been cleaned up and sanitized since it's a hospital.
Suggested correction: The blood is on carpet which is very difficult to clean as it's such an absorbent material. The carpet will keep the stain, but as long as it has been thoroughly sanitised there is no issue here. Yes, the carpet could have been replaced, but hospitals don't generally keep spare carpets laying about. Plus the fact that her office isn't a treatment area, there isn't much of a hazard anyway.
Doctor's office with a blood stain on the carpet? Highly unlikely.
Highly unlikely doesn't make it a mistake.