UC managed migration guide

Right now I am doing nothing, but I am on legacy housing benefit (the really really old pre 2008 version that hardly anyone knows about anymore), this version of housing benefit will track rents as long as they are deemed reasonable (market rates), it isnt capped like LHA.
The process with my council as I discovered last year, is I inform them my rent has increased and provide them proof, then a bit later, they reply confirming they have accepted the proof and its entered in to their system. However they dont immediately change the amount of housing benefit, I have to wait for an annual review by the rent officer, which for me seems to be around January.
My cut off date for UC migration is really close to my annual rent review, I believed but was not sure, as long as my council accept receipt of my rent increase before I migrate, then even if the rent review officer changes the approved rent after I have migrated to UC, the change would be added to my transitional protection on UC. My situation is not in "the most people" as most people dont have pre 2008 housing benefit, so hardly anyone seems to know the rules on it now. I am really glad I informed them last year, as that led to a very big increase in my HB award as it was several years worth of increases, ideally I would like to know if this is how it works on the migration as it is a bit of hassle to inform the council, and is no point if it wont affect my transitional protection.

I probably will end up not submitting the new rent agreement to the council (UC will get it as its needed as part of the claim), because my thinking now is if my HB claim is closed, then there will be no annual rent review, so I now think my original thought process was wrong. However currently I only have last year's rent agreement, so I either need to wait until I get this one to do the migration or just send them last year's agreement as proof of my tenancy. Sadly the timing of my migration came a couple of months too early. So will lose about £70 month transitional protection. I dont want to wait until there is only 1-2 weeks left to submit the migration, I feel that is too risky.

Thank you that makes more sense, I accept it will be backdated of course, an example here from someone who didnt get it on their first payment.
https://forums.moneysavingexpert.com/discussion/6567207/transitional-protection

hi , I only did my UC form on Saturday and I’ve already got a letter for Housing benefit saying as from 9/11/2024 your housing benefit is cancelled because you are now in receipt of universal credit . I thought I would get HB for another 2 weeks

thanks . I think I will call them tomorrow to check they are going to pay the next 2 weeks . Is it because HB is paid in arrears ? Also is esa paid in arrears?

thank you

Also I wasnt asked for a fit note, there is an ESA question, and if you answer yes, it removes the requirement.

There is still a work search box in to to do section. I have left it blank hoping they dont make a fuss about it.

would be good to know an average time roughly? Do you know if it’s before first payment

I’ll be doing a telephone claim, I don’t care how many people tell me that it’s online based for a bulk of claimaints. I’m with Nationwide for my banking and I don’t even deal with my account with them on their app