Not sure if this has been suggested before but seems like a feature which would be useful to some users.
I often look at the ukc logbooks using the ukc website since, especially on larger screens, the density of routes on screen is far higher and its a lot easier to manually filter, get an idea of difficulty in different areas, etc as well as viewing public logbook entries and grade votes. On the summary page for a crag on the website the green Rockfax logo is next to all the routes which are in the rockfax guide at a crag. It would be great if tapping this would open the rockfax app and highlight that route in the topo.