Hi Nicholas,
The application process for the S1 has recently changed.
Now to receive the S1, you must also apply for the
A1.
You would then receive both certificates at the same time.
Without knowing your circumstances I am unable to advise which application you will need to complete, but the following link should help you further:
Are you currently living abroad? – Guidance – GOV.UK (tax.service.gov.uk)
When it asks why you need a certificate you should say ‘working abroad’ rather than healthcare,
Thank you.