You really need to spend your time looking at what is important in this exam and not being distracted by and worrying about issues that will have no relevance as to whether or not you pass this paper. As regards your question a deposit is not income and therefore would not be included
The practise question session in F6 lectute notes contains a question ( Qno. 7 ) regarding the computation of property income tax of Peter. There in the allowable deduction you haven’t included the bad debt.Why is that ?!