Posted: Wed Aug 22, 2018 5:21am
Off the top of my head, and in no particular order:
Resident bank account.
If bringing a British car, transfer it to Spanish plates. Otherwise buy a car, and make sure the dealer does the transfer to your name.
Change to Spanish driving license.
Health cover - S1 from DWP Newcastle if you qualify, or full-cover private health insurance.
Change utility bills to your name, and I recommend registering for online access.
Insurances as appropriate for car and property.
Check if you need to change your electricity supply to a different plan and/or power rating.
Landline, mobile and internet supply.
NIE.
Register on the padrón.
Register for a residency certificate.
Decide how you want to get UK TV.
Register with Agencia Tributaria for tax purposes.
Modelo 720 declaration of overseas assets if you have such assets that need declaring.
Spanish will.