Can I ask, how did you fix the points switching automatically because I've been trying to fix these on a few routes.

I know how an apporach control works and it's actually when the diverging route is slower than the line speed. But if the diverging route is faster than the line speed then approach control does not provide a warning.

Don't understand the logic behind this.

Approach control is only used when the junction is like 15-25mph, not 40mph which is where one of the flashing aspects is (up fast to up slow towards Huntingdon) and you should know the speed of it based from route knowledge and the flashing signals give you more than enough time to slow down as it goes from double flashing, single flashing to junction signal (which should be around 2-3 miles).