Process for selling a .es domain

[lesurf]

Has anyone gone through the process of selling a .es (Spanish) domain?

What is involved and does anyone know of information (in English) on how this can be acheived.

I have had an offer on one of my .es domains and I am mulling over whether it is worrth it for the sums involved, bearing in mind most things in Spain are a bureaucratic nightmare ;-)