Hi,
You will need to ask the Hungarian authorities to request a S041 certificate from HMRC.
If you have already contacted them and they have refused to request this certificate, you can request a CA9110 from HMRC.
You can request this by completing form
Get a PDU1 certificate or a National Insurance contributions statement
Please ensure that you attach a covering letter with the application advising that you are requesting form CA9110, not a U1 or Statement of National Insurance contributions.
Thank you.