I've received notification from HMRC that my Self Assessment submission for the year ending 2020 is not matching the P14 information one of my employers provided them.
The issue relates back to January 2020 where I did a single contract through an umbrella company before moving into permanent employment.
The payslip I was issued shows a rebate of £1,333.20 however this was not included on my P45.
The self assessment information was completed by my accountants at the time based on the information provided on the P45.
I am now being asked by HMRC to pay an additional £1,333.20 in unpaid tax and £68.13 in interest.
Does anyone know if it's possible to include rebates on a P45 (e.g. a negative amount)?
I'm not sure if it's an issue with my employer for not having included the rebate on the P45 or a me issue for not having realised.
If anyone has any advice on how I should proceed it would be very appreciated.