Acquisition of the Sponsor (partially) and eligible to apply ILR

Hi All,
Quick question regarding ILR application.
Background
I will be get eligible to apply for ILR via the Tier 2 visa / skilled worker route on 17/10/21.
Situation
During earlier this year, I moved jobs joined a company A in April’21 who sponsored my latest skilled worker visa.
Now in June’21 part of business (i.e A1) of A got acquired by US company B. I was TUPE as part of this acquisition and moved into new entity formed A1.
One of UK entity (i.e. B1) of US company B had sponsorship license in UK and therefore via SMS system B1 applied to home office - change of organisation (and for expanding the branch to take in A1) and transfer of skilled worker sponsorships within 20 business days of acquisition.
Query
Per Home office timeline, they will be responding back on this application by B1 in 18 weeks which is supposed to end on 03/11. However - as I will be eligible to apply for ILR on 17/10 - do you guys think I can go ahead apply for ILR on 17/10 (explaining my situation in a letter) ?
(My employer letter will be given by A1 (also payslips) however last sponsorship was granted by A)
Need to apply to ILR as need to travel to India as early as possible - that’s why the rush.
Thanks for your help

The rules (SW 24.1) require that the sponsor in your most recent permission must still be approved by the Home Office to sponsor Skilled Workers on the date of decision.

The employer letter must be issued by the sponsor and as A1 is not yet on the sponsor register the HO will probably hold over your ILR application until they are.

Remember also that while your application is in process you shouldn't travel outside the UK because if you do the application will be treated as withdrawn (immigration rule 34K).