In a nutshell Parental Responsibility gives both parents equal "responsibilities rights, duties, powers, responsibilities and authority which by law a parent of a child has in relation to the child and his property."- Children Act 1989
Shared parenting means parents share the decisions and parent together. Residence determines where a child lives and shared residence is when children "live" in two homes. Shared residence doesn't have to be equal time 50:50, it can be in different proportions.