First tier tribunal was allowed, possible to request a change of circ advance?

Hi, I have posted before and used the guides so thank you for previous help.

Quick summary:-
04/04/2020 initial claim for UC made, conditions and their effects disclosed (dwp have noted that I self certified from this date due to covid, I didnt even know lcw/lcwra existed as nothing had been said)
I had recieved sanctions in the year following this due to my conditions and when I requested to be contacted via my journal as a brain aneurysm and rare neurological condition leave me unable to communicate via phone I was eventually asked to submit a fitnote (which I believed to be just for the phone call as still had no knowledge of lcw/lcwra)
08/06/2021 I supplied my doctors fit note which listed the aneurysm/neurological condition but also the anxiety & depression these cause, it was reported as a health change and they took that as accepted as application for lcw/lcwra and they say I was reffered for wca
27/06/2021 They sent out a UC50 (its arrival was the first of my learning about it) I really struggled with this form but managed to complete it with my teenage daughters help and needed to make copies and return it
19/07/2021 reminder issued including warning failure to complete would lead to the claim being closed. This caused me to panic and I sent the form off with original documents and no copy of my answers. (In the bundle they include a statement that it was never recieved but due to conditions including mental health they allow it to proceed to be considered for assessment
NOTE: in my 'bundle there is a comment here stating "following consideration of the paper based evidence, an approved healthcare professional (HCP) decided a medical assessment was required to establish *name* level of functional ability."
06/10/2021 I had my telephone assessment, during the call the assessor did reference my UC50 but I have no proof
19/10/2021 DM carried out an assessment and awarded LCW but not LCWRA and I was notified of the decision
20/10/2021 I requested the assessment transcrips and statement of reasons, I continued to make this request as regularly as my conditions allowed and still have not recieved them to this day.
20/01/2022 I requested a MR without seeing the transcript or WSOR
22/02/2022 the decision was reconsidered but not revised HOWEVER "the start date of the LCW was revised to 04/04/2020 (evidence pages 86-95)". Notification of this was added to my journal on the same date
23/08/2022 Appeal lodged, I included a downloaded copy of the UC50 completed using my notes/rough drafts from before so the content was the same but may have been worded slightly different. The appeal is late however the reason for late appeal (unknown pregnancy/birth and being made homeless) has been accepted.
25/01/2023 Tribunal hearing, my appeal was allowed.

Apologies for so much info upfront but its a long and confusing set of circumstances. I have tried the search function but cannot find any further info so my questions are:

1 - as they revised the start date of my LCW to 04/04/2020 on 22/02/2022 now I have been awarded LCWRA should that start from then or will that revision be discarded and revert to 08/06/2021 when they took my fit note as application?

2 - I am aware it takes 4-6 weeks to process. Is there any point in requesting a change of circumstances advance? as well as the LCWRA element it lifts the benefit cap which currently causes a £773 reduction each month in addition my youngest son is ignored due to the 2child limit from which he is actually exempt, because of the benefit cap I never addressed this but have now submitted the NCC1 form. Do any of these changes qualify for an advance as we are barely surviving and even just a small payment would make a dramatic difference?

3 - irrespective of the date they use for the claim I would expect there to be a bit of backpay due. Is there anywhere I can read the rules regarding them using the backpay for debt recovery? I am one of the people who has had notices that their entire tax credit awards for previous years (multiple) are considered an overpayment and needs to be repayed with no way to appeal or even get the details and I am fearful the whole lot is going to be swallowed up by these false overpayments.