Turning 35 during a UC payment period - how does this affect LHA rate entitlement?

I have a client who is currently 34 years old and is receiving the shared accommodation rate of UC towards her rent. Her last UC payment period was 10/1/2024 - 9/2/2024, paid to her on 16/2/2024. Her next payment period is 10/2/2024 - 9/3/2024 and will be paid on 16/3/2024. She is turning 35 on 28/2/2024. Once she is 35 she will qualify for the one bedroom accommodation rate. I am trying to advise her on what she should expect to receive for her next UC payment. I cannot work out exactly how UC will pay her in March because she turns 35 in the middle of her payment period. Is it calculated by what she is entitled to each benefit week, or each day? If it is by week, as 28/2/2024 is a Tuesday, will that week be considered a week she is entitled to the shared accommodation rate, or the one bedroom rate?
Her tenancy began on 10/9/2022.

With few exceptions (and this is not one of them) changes of circumstances occurring during an AP affect UC for the whole of the AP, so she should get the 1B s/c rate from 10/2/24.

Although this is a change that DWP ought to deal with on their own initiative without the claimant having to report it, I would leave nothing to chance and I would put a reminder on the journal before 9th March

Thank you! And yes I will very definitely remind them.