Slowly, they don't look that bad.................
There's a set just outside Pangbourne that's probably as steep, but near enough straight, as long as you keep the wheels rolling its fine, the real puckering moment is if you pick up speed and end up locking a wheel trying to control it. Either let off the brakes and try and ride it out with even more speed, or keep trying to slow down and hope the whole bike doesn't go rubber side up!
If it were me I'd give Jedi's description a try (but keep right to start surely?) then when that doesn't work, straight down the first bit and cut the corners