Travelling while Citizenship application is processed (AN)

[elk4uk]

We've been granted ILR a year ago, so can now apply for naturalization/citizenship (form AN). We'd like to travel outside the UK in 2.5 months time.

So my questions are (granted, there are no delays and applications are processed normally with passports being returned to us in time for travel):
1. Do they permanently take away the residence card?
2. If residence card is permanently taken away, will we be able to travel and re-enter the UK before getting UK passports? On what grounds? Are an approval letter and our old passports sufficient?
3. If we apply through NCS, will they copy and return the residence card on the day of application?
4. Do the NCS return ALL DOCUMENTS, if application is submitted through them?

Thanks!

[neoseal]

NCS will return all the original documents. you can travel using your passport and BRP to re-enter uk.