Live in landlord moving out

I'm a live in landlord, doing tax returns using the 7.5k allowance until now. I plan to move out to live with my partner permanently and my housemates will continue to stay in flat. I understand I'll not get 7.5k allowance once I move out. I have 3 questions: 1. I can move around Apr 6 to keep calculations easier for the year. If I fail to move by Apr 6, how is tax calculated? 2. What do I need to send to HMRC to show that I've changed address? 2. Assuming Im no longer living in rented flat from 6th Apr, should any repair expenses incurred after that date on that flat such as roof repair expenses, service charges, be treated as expenses deductible against revenue?

Hi,

You can claim the full rent a room relief as long as it has been your home for time within the basis period (tax year).

HS223 Rent a Room Scheme (2023)
PIM4001 - Rent-a-room: overview

You can write into HMRC to notify a change of address.

Self Assessment: general enquiries

If you have incurred expenses wholly and exclusively for a rental business then please see this guidance.

PIM2010 - Deductions: general rules: applying the wholly & exclusively rule

Thank you.

Hi, you have only answered 1, but ignored 2, but not 1 and 3. I'm familiar with rent room scheme (if you read my query I've mentioned that). My question were because of my transition to live in landlord to live out landlord. Please read questions 1 and 3 and kindly answer them.

Hi,
If you leave the property and reside elsewhere you will apportion the amount of rent a room allowance upto the date you ceaed to live in this is covered in the guidance as you know.
From the point you begin as a landlord operating from outside you will prepare incomes and expenses  as normal accounts of income from property as and when they arise as you are now trading as a landlord form that date of change. 
Thankyou