Hi,
I applied for one, they told me as long as you state that it’s with the HMPO in Durham it won’t affect the passport application. I should have by ETD tomorrow, it was so easy to do online and they called me from the Embassy to verify a couple of things when I forget to include a transition country (Bulgaria) I didn’t even have to do a formal interview and they courier it. Obviously make your own inquiries because each circumstance is different. My passport is definitely not coming on time now, but pleased to have the ETD on the way.
Chris