Match the window before the distance.
Compare a London workday window with a Watford home-area window; do not assume the same meeting side suits both.
Starting around London
At the London end, use “Commuter-led weekday windows make station access more useful than a simple mileage figure.” as a scheduling prompt rather than a claim that the whole route is local.
Planning around Watford
At the Watford end, compare a London workday window with a Watford home-area window; do not assume the same meeting side suits both.
Compare both local pages
Treat each town as a separate local context, then use the overlap planner rather than assuming the full route is convenient at every time of day.