Taking the Original GWR▸ area, the North Wales seaside photos might be of interest
The North Wales Coast line was
LMS▸ (
LNWR▸ ) not GWR
Indeed. There was no geographic monopoly. LMS (LNWR) lines into North Wales, and
SR‡ (
LSWR▸ ) into South East Devon and North Cornwall are notable incursions - and there are others such as the Heart of Wales line. If you look back just a couple of years before the 1923 grouping, the Cambrian lines were another company too, but taken over by GWR in (? - check) 1922.