Gap between end of current visa and start date on CoS

[Doctor123]

Hi. I am a doctor on a Tier 2 visa for the past 2 years. My current visa will end on 18/08/17. I have a new job WITH THE SAME SPONSOR who will issue me with a CoS to apply to EXTEND MY TIER 2 VISA (this is not a new visa application). However, because my new post starts on 04/10/17, they have advised me that the start date on my CoS has to be 04/10/17.

My concerns are:
1. I understand I can stay in the UK even after my visa expires as long as I have applied before the expiry date. However, what happens if I receive a decision quickly, say by the end of August? The start date on a tier 2 visa can usually only be a maximum of 14 days before the start date on the CoS (so 20/09/17 in my case). Does this mean that I would have to leave the country when I receive my new visa and only come back when it's valid? Or does this only apply to NEW tier 2 applications and not to visa extensions?

2. I was hoping to apply for the Indefinite Leave to Remain next year via the 10-year long residence route (first came to the UK as a medical student in August 2008). Would the fact that there will be a gap between the end of my current visa and start of new tier 2 visa affect the "continuous residence" requirement that I need to meet to apply for an ILR?

[iworker]

1. its no problem.
2. there wont be a gap. you will be fine for 10 years as well
the timeline by HR seems fine and u will be fine.