Well, the first thing you need to do is make a subject access request for the bus video footage.
The number plate of the bus that stopped next to you is LJ61 CAA and
https://bustimes.org/vehicles/711 says that bus is on route 144, according to
https://tfl.gov.uk/modes/buses/who-runs-your-bus route 144 is operated by Arriva London North Ltd and according to
https://ico.org.uk/ESDWebPages/Entry/Z5592665 the DPO is sheltst@arriva.co.uk
Therefore you should email sheltst@arriva.co.uk right away (hurry up as the footage is kept for a limited time only):
Dear Arriva London North Ltd,
On 17 October 2023 I was involved in a road traffic collision just before 8:28 am, I pulled over to check for damage to my car and a TFL bus pulled over next to me, the number plate of that bus is LJ61 CAA and my number plate is J44 MNY.
The bus driver told me that he had witnessed the accident, he had caught everything on the bus CCTV and I should contact TFL for a copy of the footage. This bus appears to run route 144, and TFL's website tells me that route 144 is operated by Arriva London North Ltd and that I should contact you directly for a copy of the footage.
Would you therefore please provide a copy of the footage showing this collision, I attach a copy of my driving licence and V5C as proof of identity.
Yours faithfully,
While we wait for the footage, please tell us everything you can about the collision.
This is the council video: