Public Health England in partnership with Business in the Community have developed a toolkit to help employers understand the signs of domestic abuse. It includes information on identifying those using abusive behaviours, those at risk or who are being harmed and how you can support your staff in receiving help.
A copy of the free toolkit can be found here
In addition to this you can contact members of the Domestic Abuse Intervention Service at Hackney Council, who will be happy to discuss any questions you may have on the subject.
Contact: email@example.com or firstname.lastname@example.org