Tecatel is a manufacturer based in Spain. I'm not sure if they produce inside the country but their dishes as far as i've read from several people in Greece are of high quality and surely worth the money.
_http://www.tecatel.com/productosX.php?fam=01&subf=0102
Aris is just a greek relabeling for Famaval, a portuguese dish manufacturer. Most people i came along say they are very effective dishes and also worth for the money. Though there are some opinions that it's better to invest in a professional dish which does cost much more.
_http://www.famaval.pt/en/tiki-index.php?page=antenas_230
_http://www.famaval.pt/en/tiki-index.php?page=antenas_310
Nearby Airports can be a problem indeed. I have heard much about planed blocking the signal for a very short time (longer if the air corridors are often overcroaded as in Athens) but what you mean fantom007gr might be interference. Do you know if Eleftherios Venizelos Airport East of Athens uses terrestrial C-Band for communication ? I would have thought that only VHF is used by plane-tower communication.
For C-Band you will need a receiver that can change the LOF to 5.15GHz. I am not sure if invertion still is needed but most today's receivers should be C-Band compatible since made in Asia this band is a must for millions of people.
The LNB should be preferrably cover the full
.4-4.2GHz and it's much more easily to install a flanged LNB in a Prime Focus Antenna on its feedhorn. In Offset Antennas this might become a big problem because you will have to know the exact f/D of the dish to find a suitable feedhorn. Otherwise you will lose a lot of signal.