Hello and welcome to the forum.
Interesting post however this is not really how its done down here but if you explain your requirments in more detail I am sure someone will help on the forum.
There are no formal qualifications for this role as I know it much like the UK, and as for references I would imagine this to be possible but as the demand for such a service is very low to non exixtence I would imagine no agents have a portfolio of satisfied clients they could provide instantly.
As someone that has studied the property market in Andalucia and purchased too you do need to be on your Toes and be vary wary who you engage I speak from personal experience.
Personally I would go yourself and speak to the Presidents of the communities you like or if its an independent Villa just visit local agents in the areas you prefer.
And finally for every one good agent there are 10 idiots who will take you to the highest bidder.
Good Luck
PM me if you need more info
Rod H