Superb photo. Agree it's probably a seaside location (assuming that those are shells behind Charles)
Bertram's bicycle is a 'Facile' - mid to late 1880s, & very rare today: https://onlinebicyclemuseum.co.uk/1884-ellis-co-facile-lever-operated-safety-bicycle/?tax=tour&tid=36
Glenrosa was/is indeed a whisky, distilled on Arran. Recent bottlings are perhaps best avoided:
Alongside the mirror is what looks like a gas pipe, but it seems to branch out into two strings of bulb sockets. If so that could push the date into the 1920s.