From Hinshaw Endurance:

Run Workout 1: 800m Progression

8 x 100m

20sec b/t reps

3min b/t #1 & #2

.

Run Workout 2: 800m Progression

2 sets: 4 x 200m

60sec b/t reps

3min b/t sets

.

Run Workout 3: 800m Progression

2 sets: 2 x 400m

75sec b/t reps

3min b/t sets

.

Run Workout 4: 800m Progression

1 x 800m max effort