Tax exemption as a United Nations individual contractor

Hello, I worked as an individual contractor for one of the United Nations specialised agencies and received an income for the work during the 23-24 tax year. I have a couple of questions regarding the tax exemption related to the United Nations. 1) As an individual contractor, would I be exempt from UK income tax as per the Specialized Agencies of the United Nations (Immunities and Privileges) Order 1974 No.1260? 2) If yes, am I understanding correctly that I would not have to submit a self-assessment for this income? 3) I already filed a tax return for the above income for the 23-24 tax year under the category of foreign income. Provided that I was exempt from the tax, please could you advise what steps I need to take to ask for a refund in this case? Thank you very much in advance.

Hi,
This cannot be answered on this forum as evidence of your contract would need to seen as to who you actually worked for and we would then refer the matter to  our specialist team for them to review/reply.
Thank you.