I hate putting a dampener on everything, but our fast track took more than a week.
We applied for a first child passport when it said it would take 3 weeks and got stuck in application processing. Luckily we have two birth certificates so went with the second one and a cover letter withdrawing our application early on 14th March. We got our first birth certificate back on 23rd March, so within the two weeks. Royal Mail very good re sending updates and bringing when they said.
‘Fast track’ passport only arrived yesterday morning (24th). We were given an incorrect/invalid reference, so couldn’t even chase it. Just lost in the HMPO fun vacuum. Issue date is over 7 days after our appointment, so not TNT that were the problem. We only got a message to say it was coming the day before we got it with no real indication of when that would be.
Either panic early and chase that birth certificate until it’s back or perhaps ring and check that they can’t use their existing scan of it for your fast track application? I found you get helpful and unhelpful plus conflicting information from the helpline, so ring a few times until you get someone that genuinely sounds like they know what they’re talking about. We took bad advice early on and it cost us a couple of weeks. If they’ll accept their existing scan of the document, then you could do the same as us and save the stress of waiting for the return of the birth certificate.
Only other tip is to keep refreshing the appointments page as they release them in batches and you can probably get one that suits you.
It’s all horribly stressful. Good luck!