Hi Dirk,
I didn't register the birth with the UK government. It seemed pointless to me because you can apply for the passport without it. If it was required to get a passport i would have.
I appreciate you posted a long time ago so you may have already gone about it.
I hardly log in here now but i came back to the thread because i'm applying for my youngest's passport now.
From what i can see the process remains the same. I haven't noticed any big changes in the requirements from reading the UKGOV site and going through the supporting documents.
I'll post again once we have the passport and give a bit of an update.