Nice video.
Which services will be using the flyover? Does it go from Newbury/Basingstoke over the mainlines in to Reading?
The flyover carries the up and down main over everything else, so basically anything on the mains to/from Didcot. It is the existing two curves from Reading West, and the new curve from Reading West towards the relief side of the station that stay on the normal level.
In the video linked earlier, at 1m20s is the west curve box towards Reading West. Then a train passes and you don't see the next underpass, this is for what is known as the 'Festival Line' and connects the reliefs towards P3, P7, and P8; primarily for XC reversals towards Basingstoke. At 2m0s you can just see the concrete box structure that forms the underpass for the 'Up and Down Feeder lines' - these allow for trains between Reading West and the relief side of the station, and also towards P11 (the up main loop). The latter feature is there mainly for trains from the Westbury direction to reach the up main by crossing under the down and up mains that go through P9 and P10 respectively.
Picture added below to help with the general layout, I've rotated it 180 deg so that the first underpass you see in the video is on the right.
