Great news, hope you will get your passport soon.
They did not provide me with any tracking info despite them saying that I should receive an email or text with a tracking number.
What you can do is follow this link https://mydhl.express.dhl/fr/en/tracking.html#/track-by-reference and use your HMPO application number as shipment reference (just the numbers, no letters). Leave all other fields as they are and hit Track. Do not worry if the result says that there is nothing found, once DHL picks up your passport the system will update. It took just under 48 hours for me to find my tracking number via this method.
The way to find the tracking number for the supporting documents is exactly the same.