Travel with other passport when appplying british passport

[moodbuilder]

Hi,

I submitted my British application 2 weeks ago but still haven't received the interview letter. I checked with IPS they are processing and no news of yet. I have to travel to Paris in 2 weeks time so I need my BN(O) back. it seems I have to write a letter to IPS and takes longer than a week to get everything back. so, i wanna ask.

1. If i travel with my HK passport will the immigration in eurostar/airport check my uk arrival date? (as i dont have ant stamp with my other passport)

2. Will they be able to know I'm away during my passport application?

3.Will it affect my British passport application?

Thank you very much