I have started the journey to swap Temp TIE to Permanent.
Initially I could not get an online appointment,the response was always non available to you at this time.(I went online because this was the recommended method)
I was going to wait until after the 6th Jan and then phone.
However I was bored and tried again to my surprise with success.
I now have an appointment on the 31st Jan.The earliest available!
my route:-
google search Sede Electronica administraciones publicas
Select Extranera
Select Cita previa de extranjeria. Scroll to bottom of this page push "acceder al procedimiento"
Next few bits fairly obvious.
If no dates available try another day.or Telephone 928 856 282
There is also another link via UK Gov but you need to select "if you registered before 6
July 2020"
I will be going in with copies of green cert,padrons old and new, copy of previous form 023, article 15 and anything else I can think of.