To [name of manager/leader, if known]
I would like to make a complaint about an incident that occurred on [date] at [location of incident].
I was asked by [staff member name, if known] to stop breastfeeding my child. [Include further details of incident here if necessary, such as the manner of the employee, time of incident etc]
My right to breastfeed my child in a public place is protected by the Equality Act 2010 and based on this incident I believe your establishment/organisation/club [delete as necessary] is acting unlawfully.
I would like an investigation into this incident to take place and expect to receive a response from you explaining your findings on the matter.
I will look forward to hearing your substantive response within 14 days.