British passport and documents sent while I'm away

[cc_rock]

Hi all,
I applied for a first British passport (after naturalisation) a few weeks ago and based on the timelines posted by other people I was expecting to have it by now, but for some reason it's getting delayed..
I want to travel back to Italy and I am now thinking to take the risk and use my national ID card (the guidance says I can still use it to enter the UK until October 2021).
The issue is, though, that probably my passport and supporting documents will be sent back to me while I am away and I won't be able to collect them.. does anybody know what happens in that case and how long will the courier keep them before sending them back? The DHL site says they would keep the passport for up to 30 days (which would be more than enough for me to come back and collect it) but doesn't say anything for the documents.. I have chosen the "secure delivery" option so I think they would be sent with DHL too ..
anyone has any info or advice?
Thank you very much

[CULLINAN]

You will need to contact TNT. It can take 3-6 weeks for the passport and documents to be returned.