The village shown in the title shot is North Woodchester near Stroud, Glos
In the programme, they mention of a multi-storey carpark in Nailsworth. Nailsworth is in fact a very small town, and has nothing of the sort. The closest place to have a multi storey carpark is Stroud, where the programme is filmed in, and the surrounding areas.
The shared house which Cass lives in is the same house used as Morse's "future house", in filming of Series 6 of the Inspector Morse prequel Endeavour (see S06E01 - Pylon)