I have little expertise in the area of soundtrack music. It is my opinion that they largely serve as comforting souvenirs almost regardless of their quality.
John Lunn’s score does rise above the ordinary with its quasi post minimalist gentle music for this mini cult film. He is not Prokofiev or Herman but that level is not what is needed to support what is in the end a well written and well acted/directed costume drama.
Lunn does not burden his audience with obtuse or even obvious references to British music (folk or classical). No quotes from Nimrod or Rule Britannia (thank God). Just competent and unobtrusive incidental music for a decent film. Doubtless there will be a few live orchestra performances concurrent with screening the film in a concert setting. Enjoy the memories.