Switch Employers - Tier 2 General

Hi Guys,

Looking for some advice on my situation. Here's the details:

- Currently on a Tier 2 general and have a new offer starting on Jan 24 2022
- I have a 3 month notice period in my current role
- I'm looking to travel to Australia from Oct 14 and return to the UK beginning of Jan

The questions I have are:

- Am I able to complete the whole visa process whilst in the UK before I leave? Is that enough time and also considering the start date of Jan 24?

- If I was to do the whole process from Australia, would that impact by eligibility for ILR down the track?

- When would I put in my 3 month notice period? My new employer is saying that once the visa is approved, I'm technically not allowed to work for my current employer (I don't think this is true as I will need to work during my notice period anyway)

Any advice would be much appreciated. Thanks