During the main part of the day, the Marston Vale is hourly

If I remember correctly, Ridgmont is a passing place on the route.
For anyone wondering how I got that, it was pretty straightforward. LM 153, closer to London than Bedworth = Marston Vale Line. Presence of road in background approaching roundabout limits numebr of options; Ridgmont stuck out as the most likely in the map.