lost foreign passport and applying for british passport

[JW123456]

I was walking down the post office yesterday to send off my first British passport application and once I had arrived there I checked if I had all my documents only to discover that I had lost my latest foreign passport on the way, I then went and searched for it but I couldn't find it anywhere so I went back to the post office and the check and send lady said it would be okay, I just would need to fill out a form to say I had lost it and my application may be delayed because of this.

I filled in the form and sent my first British Passport application off, by the time I had gotten home a man came to my house saying he had found my passport.

What do I do now? Do I send the passport over to the Passport Office and just write a note saying, I sent my application yesterday and lost and found my passport yesterday? Or is it too late?

[CR001]

Contact the passport office advice line and ask them if you should send it now or wait for your reference number.