Yes you do. But you are the recipient of a catch all form , with a catch all box 28, so it's hard to know what the box 28 amount is for. Possibly some payroll deductions being reimbursed.
In any event, it appears you wrere an employee of HMV, not self-employed.
In such circumstances my suggestion is to report the amount as "other income, not on a t-slip".
It will go on to line 130 of your return.