Pause on the main road, check the car park to see if it is safe to enter then decide which bay you are going to reverse into. NB your point of turn is after the door handle on test centre door.
With your speed slow (old person walking pace), steer right into the car park checking position,15cm from the bay ends as you pulling up on the left. NB reference point on dash. Check mirrors and pull up so you are 1/3rd across the bay you want to reverse into.
Open your window, P O M then with your speed slow apply full right lock (no dry steering). Keep observing everywhere especially to the right looking for pedestrians and other cars stopping. Once you can see the left line of the bay pointing to the left corner of the car in the left wing mirror. Stop
Place car into reverse, P O M then with your speed slow apply full left lock, ensuring observations are made over shoulders and every 2 seconds you look in another direction. Assess accuracy in left wing mirror and alter steering as necessary using the left bay line as a guide. Straighten up as you become parallel to the bay ,if you cannot see the right line in your right wing mirror STOP and drive forward steering right until you can see right and left lines of bays , then reverse and straighten up ,looking over shoulders mainly .Stop when in line with the tree to the right. NB: If any manoeuvre is not going right STOP and reposition you, all others have priority, keep the car slow and look everywhere.