p85 query

Dear HMRC, I am currently, taking a work break for a couple of years and I declared my P45 date in the 2023/2024 Tax year. I have the opportunity to move abroad but I am unsure If I will go and If I do for how long? Should I fill out a p85 regardless or wait until my time abroad consists of more than a complete Tax year? The reason for asking this is that I think my UTR will be cancelled and I will lose my gov gateway login which will be a hassle for the future when I return, if I only decide to move away for a short amount of time. Furthermore, the P85 form asks how many days I will be in the UK for the next 3 years, this will be very difficult as things are subject to change, How would you address this question? Furthermore, I have and will not make income in the 2024/2025 income, should I still do a tax return anyway for good order or will HMRC know that this is the case? Thank you for your help.

Hi,
You should check whether you need to complete a self assessment tax return at Check if you need to send a Self Assessment tax return.  
If you do not, let us know by contacting our self assesment helpline on 0300 200 3310 or our webchat facility at Contact HMRC.  
Your government gateway ID and password will not expire.  
The P85 is asking for estimates, as no one can predict the future.  
There are no tax implications if your estimate is over or under.
Thank you.