Updated SA Return - HMRC Treatment

Hi folks. Looking for some guidance on how HMRC will treat my updated 2021 self assessment tax return. My employer has a share scheme that when actioned, is treated as salary. I was living and working in the UK, then moved abroad. In short, my employer screwed up the vesting/transaction dates when I sold some shares and apportioned too much 'salary' in the UK, instead of my new country. To correct this, they issued a 'corrected' P60 with what I should have shown as income and what should have been taken as witholding tax. They also updated the income on the appropriate tax docs for my new country. However, my employer did not adjust the actual payment to me or the actual tax taken because the total income was correct (just the reporting split per country was incorrect) and they said HMRC would correct the UK tax withholding. I submitted a 20/21 tax return at the time and now need to resubmit. Numbers are for example only. Old P60 States income/salary - 100k States tax withholding - 45k Tax refund once SA tax return was filed - 12k (which was paid in 2021) Total tax paid inc refund approx 33k New P60 Income/salary - 60k Tax withholding - 25k Tax refund - ? My questions are: 1) When I resubmit my tax return with the new P60 details, will they take into account that I've already actually paid around 33k in tax (45k - 12k refund) and therefore issue an additional refund of approx 20k? 2) Do I need to call this out anywhere on the return itself or is it something HMRC will automatically do? 3) OR do I need to go back to my employer and ask them to refund the initial over-withholding to match the P60? All advice appreciated!

Hi

Any amendment you make will take into account the previous figures you submitted. as its an amendment, any refund due will not be issued automatically amd you will need to telephone 0300 200 3300 to have this issued.

Thank you