Questions Around ILR Set(M)- Unpaid leave & Travelling

I have some questions surrounding an ILR application, going via the 5 year spouse Set(M) route, which I'm hoping someone can help with.

My wife and I are planning to set off to do some travelling abroad, which unfortunately collides with my ILR application and what sounds like a lot of unexpected delays from the Home Office. Hoping someone can help with some specific questions so we can try to make some plans:

1. Financial Requirement & Unpaid Leave:
My wife is on a £57k salary but has just gone on sabbatical(unpaid) in the last month. Her payslips for 5 of the 6 months will reflect her full salary, with the most recent payslip being much less, as she's only worked for 1/3 of a month. She has a letter from her employer confirming her annual salary and 6 month sabbatical. The question is- can we assume we still meet the financial requirement if she is now on unpaid leave, considering that she's earned over £18K already in the last 6 months? I read in the guidance that they will take the lowest months salary of the past 6 to base your income from, despite her already earning over £18K total in the last 6 months.

We also have further joint savings of approx £6k, and I could use my self-employment income(I have around £30k in a business bank account) but this looks much more complicated from a document submission standpoint.

2. Application Date:
Am I correct that I can apply for ILR on 10/06/2022, based on the 08/07/2017 issue date of my initial FLR(M) BRP?

3. Abroad When Submitting Application:
We are planning to be travelling in June, when I need to submit my application. Our residence is in the UK and we will be 'applying from within the UK' for the application. Do I need to be physically in the UK when I submit the application online and book a biometrics appointment? Or is this only for submitting/attending the biometrics appointment and the waiting period thereafter?

4. Leaving UK Without BRP?
Am I able to travel as soon as I receive a decision on ILR? Or do I absolutely need to have my biometrics card with me when I leave the UK? As I could have someone courier this to me abroad when it arrives in the post, for my return travel to the UK. I need to be able to depart the UK as soon as I can for urgent work reasons, but I don't want to invalidate anything.

Any help or guidance is much appreciated!

1. You would need to read Appendix 1.7 to understand what is required to use your income as self employed.

2. Yes.

3. You need to be in the UK to apply and wait for the outcome. If you are not going to be in the UK and there is enough visa validity to apply once you return, then apply once you return. If you apply and attend biometrics and then leave the UK, your application will be considered withdrawn and you lose the fee paid.

4. BRP cards are delivered by Courier and can take anywhere between 7 working days and 3 weeks. You do NOT need evidence of a visa to leave the UK.