The free software is ok at a very basic level and usually limit the number of employees you can have. HMRC have a list of the free providers at https://www.gov.uk/payroll-software/free-software Brightpay no longer has a free option.
Without knowing more about your client you are also likely to need to process pension information too which you should bear in mind when you select the software to use. Think about calculations, submission files, statutory communications etc.
Also, I notice you don't have PM.Dip showing. If you haven't got this, then you will not be able to offer payroll services under your practice licence. Your only option then would be to complete the qualification or sub-contract to someone else who is able to offer it.
Hope that helps, or, feel free to get in touch.
Hi I see this is an old post but I have taken on a charity with 5 employees and want to know which of the free payrool software options anyone would recommend. I need to be able to print payroll slips