To reverse safely you ideally need a neck like an owl.
Reversing in a straight line is specifically included in which of driving test manoeuvres listed:
Stop on the right
Bay parking to the left
Bay parking to the right
Parallel parking
When reversing in a straight line, it's usually best to look back over your left shoulder.
When reversing for a short distance downhill in a car fitted with manual transmission you control the speed with:
Clutch control
The accelerator
Footbrake control with the clutch pressed down
Footbrake control with the clutch up
You are legally permitted to unfasten your seatbelt while reversing.