Thanks. So S1 is continuing to be issued when people reach retirement age? But only to those who were present in EU before Dec 2020, right?It may not be now, but once you reach retirement age, if you cannot get an S1 from the UK because you were not already registered as a resident in Spain by 31 December 2020, the cost of private health insurance will increase greatly. Even if you access public healthcare by paying into the Convenio, the cost increases from €60 per month for someone aged 65 to €157 per month for someone aged 65 or over - and as xabiachica said earlier, in addition you'd have to pay 100% of the costs of any medication you'd need, whereas with the S1 you qualify to pay only 10% when you become a pensioner (and that's capped at €8 per month for those whose income is below €18k per year or €18 per month for incomes between €18-100k.
It's a real Catch-22 situation for you, unfortunately. I really wouldn't recommend anyone to reduce their earnings so drastically in the years leading up to their retirement unless they had enough of a financial cushion to cover the shortfall, and you have to think beyond your retirement date to make sure your income in retirement would be at least adequate.
On another note, does anyone know whether the pension updating arrangement (which again only seems to apply for those present in EU before Dec 2020) will continue to apply if one later moves to another EU country?