TfL standard practice. People who live in London, who after all are far and away the biggest users, are absolutely used to this.The whole naming lines is a nonsense, it would have been far easier, cleaner and simpler to use Line 1, Line 2 etc. Easier to remember, easier to give tourists directions, no issues with mispronunciation, would clearly separate over ground routes from under ground routes, and so on...
Frankly what underlies most of the complaints is discontent at the names chosen due to political bias. Londoners, of who l am one, gave the Mayor a new mandate so frankly those from elsewhere can suck it up and butt out. We don't care about rants about our mayor.
@Tetchytyke is absolutely right that use of s-bahn style numbering would have cost exactly the same.
