Although you could use services as a translation for "servicios", in English we normally use work, employment or position. The "servicios" part comes from "prestar servicios" which means to work [for] or to be employed.

So in this case, you could just use "permanent positions" or "permanent employment".
https://en.wikipedia.org/wiki/Permanent_employment

It might make the other terms easier to translate too, e.g. supply/substitute positions, internship positions, temporary positions, etc. (not sure about "servicios laborales", would that be labour-related positions, perhaps union-related?). Saludos.

Late to the party... I would propose a different approach that expresses the effective meaning of the term rather than its literal meaning. I am very familiar with the terms themselves, since my wife is a member of this very cuerpo (in this very autonomous community).

For the "servicios" part, I think "status" is the word that best captures what it's really referring to. Of course it refers literally to the services the teacher is providing to the education system, but we're really talking here about a teacher's career path. After passing the oposición, the progress from prácticas (the first year) to provisional (the next couple of years) to definitivo is really automatic, and the work is the same; the only real difference when you become definitivo is that you get to choose your post and it is your "property", whereas in the prácticas and provisionales stages you are sent wherever they choose to send you, and although you're not an interino (which means you're in the bolsa de trabajo, you haven't passed the oposición), the post is not yet yours by right; you can in theory be supplanted by an established teacher and sent somewhere else. This can't happen, in theory, once you're "definitivo".

I think the best way of conveying the essential idea, as I say, is to use "status" for "servicios". From the teacher's own point of view this is what it amounts to, since what changes is not the nature of the work but your employment rights. The hierarchy which determines the "pecking order" within a department (who gets to choose their teaching groups first, who has priority for the rotating position of head of department, etc.) is how many years' service you have since you became definitivo.

It is quite common to refer to teachers that have been confirmed in their position and acquired long-term employment protection as "established", and this term is often used in referring to systems, like Spain's, where state teachers are civil servants. I would borrow this and use "established status" for "servicios definitivos" and "provisional status" for "servicios provisionales".

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Note added at 14 hrs (2016-05-11 08:19:23 GMT)
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My slight problem with "permanent" is that as soon as you are a funcionario you are "permanent" in the sense it's normally used (lifelong employment protection). The particular post you're assigned to is not permanent in the provisional stage, but then it's not permanent in the definitivo stage either, since you can apply to move at any time in a concurso de traslados. And "definitive" just doesn't sound natural to me in English.