Marked in red: Interim - to the best of my knowledge 20/- per week (a pound) was the maximum for a soldier so this could be an interim payment which would be reviewed?
Marked in pink: 20/- to be paid for 26 weeks from 10 Nov 1920
Marked in blue: appears to be LWA ? guessing at Lifetime Weekly Allowance
Marked in green: ? no idea, sorry, others may have a better idea
Boo