sachins

Hello Team, I have received a notification from HMRC regarding too little tax paid for the year 2022-23. However, rechecking the calculation with my tax advisor we have identified the amount mentioned of previous employer in HMRC portal is different then the amount mentioned in my P45 and P60 form. I called HMRC and the advisor on the call asked me to send a post with the Letter to HMRC explaining the discrepancy and also sharing P45 forms. Can you help me with the correct HMRC address to send this post, as the one I sent to BX9 1AS isn't yet delivered as per Royal Mail tracking which I sent on 13th Feb which made me wonder if this is the right address or do I need to send to some other alternate one ?