Switching from Tier 2 to Tier 1 ET with a fellowship - consideration time

[zfish]

Hi all,

I'm switching from a Tier 2 visa to Tier 1 from within the UK, after being awarded a peer-reviewed fellowship from a UK research council.
I recently made the stage 2 application and booked an appointment for the biometrics. Unfortunately, I missed the fact that the decision time (8 weeks) is so much longer compared to applications from abroad, and I have plans to travel abroad just short of 8 weeks from the time of the appointment. I was wondering:

- The 'switch to this visa' page states that 'You may also get a faster decision if you hold an approved peer-reviewed fellowship'. Does it apply to stage 2 or only for the endorsement part? Does anyone have experience applying with such a fellowship on standard service?
- How improbable it is to get a decision within 6-7 weeks? (hard to tell from timelines posted here, many of which are through the premium service)
- Will I be able to travel with my Tier 2 BRP once getting the decision letter, or would I need to wait for the new BRP (I guess that could be a delay of another 10 days or so).
- Is it possible to pay for the premium service after making the application and setting up an appointment?

Thanks a lot!