URGENT - Traveling before receiving new BRP

[LBUK2021]

Hi all, good day

I received a confirmation my RTW was approved by the home office on 9/12/21 and they mentioned they need 7-10 working days to deliver my new BRP. I'll need to travel abroad this 17/12/21 and it's likely my BRP won't have arrived. Does anyone know:

a) If there is any way how I can get back to the UK without my BRP (considering the extension of my RTW was already approved)?
b) What are the risks? I mean, is there a risk my visa is refused if I go abroad (something I'd really need to do)?
c) Can someone receive my BRP on my behalf and mail that to me?
d) If I request my BRP to be replaced, does it also take 7-10 working days to be delivered and the country I'll be?

Appreciate a quick return as time is running out.

Many thanks!