she hasn’t taken the necessary steps. She didn’t cancel her work permit and extension of stay. I’m not sure what you mean by “perhaps her former employer hasn’t finalised the cancellation” - it’s down to the individual to do the necessary cancellations, not the employer.
worth calling UK passport office accounts dept. I had a delay on my recent passport renewal and no notification so called their accounts and my credit card payment had been declined. They sent me a link to make payment and my passport was back with me in Thailand within a week. +44 300