In the Harley Quin short story The Sign in the Sky, Sylvia Dale is the daughter of a doctor in the village of Deering Vale. Martin Wylde became interested in her and terminated his relationship with Lady Barnaby.
Mr Satterthwaite described her as fair and gentle, perhaps a little bit stupid, but very loyal. Sylvia herself would tell Mr Satterthwaite that she was indeed stupid this could be an advantage because she understood how stupid people behave.