First adult passport, overseas application. Been in processing since 14 April (application submitted 18 February). It appears someone took issue with a birth certificate (which had previously been accepted for another UK passport application) (and had also incidentally been accepted for an Australian passport application). They also wanted the document used to arrive in Australia (not possible as it was a parent’s passport 50 years ago). Because this latter document no longer exists we were advised to send a letter, this was received 24 May according to tracking. On 30 May we received a reminder email threatening to cancel the application if letter was not received. This time there was an email address to reply to and we emailed a copy of the letter and a statement that the letter had already arrived there and been signed for. Since then there have been no updates or further contact.