Home office, and tax expense deductions

I have two questions:

1. Under what circumstances can one claim "home office" deductions (code 4028)? And what items can one claim?

2. What can one claim a deduction for under code 4043 "allowable accountancy expense"? (Eg. If a tax practitioner filed our tax return last year, would be able to claim that expense?)

Thank you!

1. Please go through our questions on whether you can deduct home office expenses?

2. Allowable accountancy expense is only allowable for expenses incurred related to annuity/pension income - so when you have retired basically.