I actually think they don't want it as it'll cost too much. They keep kicking the project down the road hoping people will get used to the existing situation. The tunnelling was finished ages ago, if they wanted the bridge asap, contractors should have been on-site the starting this project the day after; christ, they've had long enough to plan it.
It’s amazing isn’t it?; But then you’ve obviously never tried to build anything for Network Rail before! They really can stretch things out timewise…. Even a simple dry stone wall rebuild can become a work of bureaucratic art!