The Spanish AIP is available as a free download from the AENA website:
Servicio de Información aeronáutica (AIS) - Navegacion Aerea - Aena.es - Navegación Aérea
The requirements for off airport private sites are:
AIP AD1.1-5
3.7 CASUAL HELIPORTS
Casual heliports are surfaces that have a minima safety conditions to be used by helicopters on a temporary basis. The utilization of these fields are subject to the authorization of the terrain owner and the Agencia Estatal de Seguridad Aerea and limited to a maximum of three landing and takeoff operations a month, except for aircraft in special operations.
Hope this helps!