How to capture vested RSU in self-assessment

I am a UK employee for a US-headquartered financial firm with a tax code of OT since my earnings, as shown on my P60, are above £150k. In the 2022-23 tax year, I got a small amount of RSUs vesting (approx $3.8k) and I was taxed 60% on that RSU vesting amount (approx $2.3k). Can someone please confirm the following: 1) Should I capture the vesting of the RSUs in my self-assessment? 2) If yes, what section should I capture this, and also how do I capture the fact that I have already been taxed 60% 'at source'? 3) Is 60% the correct tax percentage for these vested RSUs? (Since any additional income I have had outside my P60 numbers was charged at 45% and so, my expectation is/was that the vested RSUs would also be taxed at 45% and not 60%) Any help on this will be appreciated.

Hi snapperdragon,

As the payment is from your employer, the income should be shown in the employment section if it is included in your P60.
You would then claim credit for the Tax in the foreign section under 'Employment, self-employment and other income which you paid foreign tax on'.
If it's not included in your P60, please include it on the box on the employment page for 'Tips and other payments not included on your P60'.  
ERSM20193 advises that when RSUs payout at the market value on what is called "dividend equivalents" in either cash or shares, such payments will generally
be taxed as earnings in the year they are received.  
ERSM20193 - Employment-related securities and options: what are securities: RSUs and dividend equivalents 

Thank you.