First, the thing that is wrong almost everywhere else
Helios is private. It is not concertado.
Its own reglamento says so three times — "privado, no concertado", "sin ningún concierto ni subvención oficial" — and the Generalitat's own school registry returns PRIVADO for it. For comparison, that same registry returns PRIVADO - CONCERTADO for Novaschool, a genuinely concertado school a few streets away in the same town. Two schools in L'Eliana, one private and one publicly funded, and the names tell you the opposite of which is which.
This matters for money and for admissions. A concertado school is publicly funded and its places are allocated through the statutory round with the baremo. A private school is not, and it sets its own process. A family that believes Helios is concertado will plan the wrong admissions route and budget the wrong number.
What it costs
Helios does not publish its fees. That is not unusual here — two of the ten schools we checked do the same — and it means the only honest answer is that you have to ask.
We are not going to put a range on this page from a comparison site. The aggregators carry figures for Helios; they are not the school's figures, and a fee taken from an aggregator is exactly the kind of number that is wrong by the second year.
The languages
Teaching is in Spanish and Valencian, with English as a subject. In practice that means a child arriving without Spanish is arriving into full immersion.
For a seven-year-old that is usually the right call and it works within a year. For a fourteen-year-old it is a different decision entirely, and it is worth making it with someone who has watched a child go through it rather than on a brochure.
Who it suits
A family that has decided to stay, wants its children inside the Spanish system and fluent, and values a school small enough that the teachers know the child by name.
Who it does not
A family that may return home, or one whose child is arriving mid-secondary without Spanish.