Working remotely from Brazil being an employee of a UK company

Hi, I am brazilian and I live in the UK under the pre settlement status (I have EU dual nationality). I work for a UK based company and have requested to work from Brazil for 1 month. They have declined my request saying that the UK and Brazil don't have a double tax treaty. I have done some research and found out that there isn't any tax implications for working for a different country under 183 days. So, technically, I could work from Brazil and only be taxed in the UK, is that correct? However, I don't know if that's the case for working from your home country (Brazil in my case). The examples I saw were from people that wanted to work from countries where they do not have citizenship. My case is: I live un the UK and pay taxes here, I am brazilian and also pay taxes there. I have requested to work from my home country (Brazil) which has been declined. Can I appeal this decision? Can someone help me get clarification on this please? Thank you.

Hi carolcmc,
The working arrangements of an individual who works for a UK company are entirely a matter for the employer/employee in question.
HMRC is solely concerned with ensuring that the correct amount of tax is paid.
If you do work remotely in Brazil for a short period of time, you are likely to remain tax resident in the UK and your employer would continue to deduct PAYE tax from your earnings.  
PAYE81645 - PAYE operation: international employments: issuing form P85
Thank you.