Many of the fictionalised building locations were actually real world locations in Dublin and Malahide, in Ireland. Meaning that many of the Irish viewers easily re-located the series to being set in that part of Ireland. For example, the fictional police station location set "in the UK", was actually the Park House office building, owned by the DIT/Technological University Dublin, north of their main campus site, on North Circular Road, in Dublin 7, in Ireland. A later scene of 2 people in a (UK) police car parked outside the "police station" clearly shows the distinct architecture of the other street-facing side of the Park House building, with the front through the car windows corresponding to the view opposite that side of Park House.
Bosham used as a waterfront location.
Considering that the entire story never leaves the UK, it may seem that it was an odd production decision to use the UK for the exterior coastal landscape scenes, and use the areas around Malahide and Dublin city for the buildings' interiors and exteriors, however, the series was shot in the Republic of Ireland, as the Government has various tax incentives to lower the cost of certain film and television productions budgets. Hence the end title credit stating "Produced with the support of incentives for the Irish Film Industry provided by the Government of Ireland." This is also why the production crew has many obviously Irish names.
Despite the story taking place in the UK you can see a constituency office for Allan Farrell TD, a member of the Irish Parliament in episode 3.