Research so far: Whitehall maps, Thames crossings, specific terrorist attacks (Downing Street mortar attack), far too much time on Google streetview trying to work this out. Now slightly worried about how my browsing history looks.
Three of my characters are trying to get from approximately Waterloo Station to Richmond Terrace, where they plan to break into a government office and steal something. Alas for them, the current government is a paranoid, surveillance-happy totalitarian dictatorship, so they can't just walk in. I'm planning to fudge over the details of the break-in itself, but I'm trying to get them across the Thames and past ridiculous amounts of security without raising too much attention.
The scenario that I've set up involves a few urban planning changes. Since the Tube is a haven for various dissidents, the government has poured cement through all of the tunnels in the immediate vicinity. There are checkpoints at each major crossing, barbed wire fencing, and extensive video surveillance, but not huge amounts of actual guards, as by this point in the story, the government is strapped for human resources and relies heavily on drone technology and CCTV, which these characters are experts in dodging.
My plan at the moment is to have them make their way across the Thames by climbing underneath Charing Cross Bridge, but I have no idea how realistic that is to do physically. (Said characters are in their late 20s to mid 30s, reasonably fit, but by no means experienced climbers.) Past that, I'm looking for a relatively inconspicuous route through the area. They've all spent a lot of time there, so they'd be familiar with back alleys and so forth.
It's also the middle of the night and there's a curfew on the city, so disguising themselves as tourists isn't an option. :( They can draw some attention, but I'd prefer it to be on the way out rather than on the way in.
Help? Thanks in advance.