Titus, I hear voices "repeatedly" in my head - "Mind the GAP", over, and over, again (the Tube). The repeated audio warning in the underground (subways) gets quite annoying. Anyhow, try to avoid the mass transit and walk as much as you can. I envy your discipline of health conscious during your travels. Have a "Pint" and a safe journey on the other side of the pond. Study the "Wonderground Map - The London Town (1928)" - Famous poster that was used to promote the Subways on the Weekends in London.

Link to Scalable map: (https://www.davidrumsey.com/luna/servlet/detail/RUMSEY₈1₂₆₀₀₈₉5522835:The-Famous-Wonderground-Map-of-Lond#)