Have got Act 6 Chapter 3 where Hunt and Ishi attempt to escape from the bomb that is due to go off. Using the leash you have to rip off an access panel and then approach the wall and (R) Climb message appears but know matter how many times I have tried I always end up back at the base of the wall. Have restarted the chapter gone back to the last checkpoint and started again. But I still get the same result. Have tried searching for patches and hints but to no avail. Anyone got any clues on how to get passed this glitch?