@LAD
Could you give a bit of detail on your US embassy appointment / experience? I’m in the exact same situation as you were in – I’ve received my UK passport back, but have been waiting on my supporting docs (US passport + naturalisation cert) for a few weeks now with no word, no update and I’m travelling to the US in 4 weeks for my brother’s wedding so am very nervous! To be safe, I have an appt at the embassy in a couple weeks in the expectation I still won’t have my passport back. So I’m curious as to your experience, how easy/difficult it was, did they seem pretty used to these requests, were they nice/helpful, what docs you provided, etc. In 10+ years of living in the UK I’ve actually never once been to the embassy!
My plan is to follow the guidelines for a second passport, so DS-11 form and signed statement explaining the situation, plus bringing photocopies of my US passport, proof of flight booking, proof of passport submission to UKVI, US birth cert & drivers license and a couple printed passport photos.
Also, when did you eventually get your US passport back? How many weeks after your UK passport?
Thanks!