My family and I regularly cycle through this junction. When we approach we stop on the detector imbedded in the road. There also seems to be a camera mounted on the traffic light as a back up. I do not believe either are sensitive enough to pick us up and so we do not receive a green signal to advance. It is only when a vehicle arrives behind us that the lights will change (this can be in excess of 5 minutes). Because of the delay, some cyclists (and even vehicles!) ignore the lights altogether.
Can I suggest that the detectors are looked at to ensure they work for bikes (note that modern bikes now contain very minimal metal components and so traditional detection methods may be ineffective) . This junction is very popular with cyclists and so they should be the priority.