The mother of seven was known to have links to London, Newcastle, Wales and Scotland, and also used the names Jade, Vanessa and Tricia as well as the surname Bradford.
Police said she moved to Dudley in the mid-1990s and frequented the No Limits club and other pubs in the area.
It is understood she and Dunkley knew one another.
Det Insp Michelle Cordell said: “We want to hear from anyone who may have known or remembers meeting Patricia, or Trevor Dunkley.
“We know she was fairly well known in both Dudley town centre and Oldbury.
“Even if you already spoke to us at the time Patricia went missing, we still want to hear from you as we gather as much information as we can to help her family find some closure after nearly 30 years.”
In 2017 the family of Lashley, who would now be aged 61 and a grandmother, issued a fresh appeal to trace her.