Purely for clarification the following paragraphs are copied from the NHS Web
page on Moving Abroad:
You can no longer apply for a residual S1 (formerly residual E106), which previously provided temporary healthcare to early retirees moving to other EEA countries.
If you move to an EEA country or Switzerland long term or plan to work in another EEA country, you will need to register with the appropriate authorities. Once you are registered to work in the country and make National Insurance contributions, you will be entitled to state-provided healthcare on the same basis as a national of that country.
If you are living in an EEA country or Switzerland and you receive an exportable UK pension, contribution-based Employment Support Allowance or another exportable benefit, you may be entitled to state healthcare paid for by the UK. You will need to apply for a certificate of entitlement known as an S1 form.
The first paragraph relating to Form E106 is self explanatory, i.e. it no longer applies. In the past people moving abroad to work could also get UK paid for healthcare for a period of time, under Form E109, until contributory healthcare in that country started, Although the second paragraph doesn't explicitly mention E109 it effectively means that it is no longer applicable. Nannies and au-pairs can use an EHIC for up to 1 year if working in an EEA country plus Switzerland. Armed forces personnel and their families can use an EHIC while they are stationed in an EEA country plus Switzerland. Nowhere does it permit the use of an EHIC card for anybody else living abroad. Paragraph three is the old Form E121 and is still applicable.