It doesn't take that long for a query for one journey; as with using a website, the staff would enter an origin and destination into the journey planner, and the list of itineraries and fares would appear almost instantly. Yes it may take a bit of time to establish which itinerary and fare the customer requires, but not that long.Rail enquires can easily take 15-20 minutes, for instance find the cheapest fares, routing, engineering works, strikes, customer assistance etc etc...
What proportion of the ticket do you think retailers should get, and would this vary by sales channel (e.g. ticket office, ticket machine, telesales, website)?