Loco Pedro

I'm also an early retiree, who has had many instances when the local Centre de Salud would not honour my E106 qualification without an EHIC.
I eventually got so fed up with this twice yearly argument for my temporary SIP card that I phoned the UK requesting a replacement for my "lost" EHIC which arrived at the UK address I gave them within a week.
In the meantime, I visited the "Accreditacion" department of our main hospital in Denia and created a fuss regarding this spurious need for my EHIC card to gain a SIP based on my E106.
A very helpful lady told me she would sort it - and she did. When I went back to the health centre, they meekly handed over another SIP.
Incidently, whilst at the hospital, she photocopied the E106 and issued me with a letter which I need to show every time I have a hospital appointment to prove my current on-going entitlement to treatment.
This has to be renewed every year with each new E106.