Investors & landlords

Thanks a lot really appreciated. 

For this parts: 

1. Gross rental income for 2021/2022 is   9 months at $1100 =$9900 plus 3 months at $1200 =$3600 for a total of $13,500 -- tax at 11.8% =$1593

2.  Gross rental income for 2022/2023 is 9 months  at $1200 = $10,800 plus  3 months at $1300 = $3900 for a total of $14,700  and a tax at 12% of  $1764

why  did you count 9 month? for both parts 1 -2

One expert  already mentioned most of people has cash method instead of accrued, per your explanation most of people in UK should take accrued method. So who can use cash method?