Hello, we have been through the process and went to Social Security in Fuengirola last Friday.
Hope this reply is not too long winded
When you got your S1 from Newcastle it tells you want documents to need to take to Social Security. Newcastle should have sent you two copies of each of the S1 form. Social security need both !!
You will need to go to the Town Hall and sign on the padron. Take with you passport and copies, nie, and we took an electricity bill to prove our address. They will check whether you owe them any council tax etc and then issue you with a padron certificate (free)
Residencia - go to Fuengirola National Police station (up the steps and turn immediately right. Queue at first desk on right and ask for an appointment. The man on the desk was English speaking. They will give you an appointment and tell you what docs you need. Make sure that before you go to the appointment you pay the fee at a bank. Keep the receipt as you will need it. At the appointment (there was an English speaking lady) they will issue you with a green residencia certificate.
When you have done above get copies of all of the above and a copy of your passport(s).
We went to Social Security last Friday around 10.30. with the above forms and a copy of our NIE (but not needed). A lot of people in the waiting area and around 6 people in q in front of us. When it was our turn I had my Spanish/English dictionary in hand (just in case) tried a bit of Spanish (buenos dias) showed the S1 letter and smiled. The female clerk took the form and asked for documents (originals and copies). When she had checked them she photocopied S1, stamped it and gave us back one copy. A card is apparently sent out within 3 weeks. We were in and out within 45 mins. If there is an emergency use your EHIC in the meantime. You can sign up at the doctors with the stamped S1 or wait for your card.
Hope that is all helpful, let me know if you need any clarification on above,