it mentions that they have policies against slavery but they are not very detailed

"Our policies and procedures are continually reviewed to enable a supportive, safe and accident-free workplace. Our employees are at the centre of our health and safety programmes where we work collaboratively together to achieve the objective of Zero Harm across the organisation"(page1)

"We recognise and understand the complexities associated with the existence of modern slavery and its potential impact on global supply chain networks and we are committed to working with our Suppliers, Customers, Regulatory Authorities and other parties and organisations, including NGO’s, to support the development of long-term solutions to this issue and its abolition. Our Purchasing teams are fully committed and focused on ensuring that we purchase materials only from legitimate companies that meet all appropriate legislation and are not in any way engaged in or associated with Modern Slavery or Human Trafficking. "