I would thoroughly recommend Crete Homes as above. They’re based in Aghios and very professional. Hilary is english but the others also speak excellent English too, so no worries about mistranslation etc. We bought from them and have had lots of work done, and we have friends who has also had good experiences. Highly recommended.
I met 3 so called "builders" when I first purchased land in Crete but was incredibly lucky to meet George from Europlan. They are without a doubt one of the best firms of architects and builders on the island and are very trustworthy. Their head office is in Agios Nikolaos and are building the large Villas for a Russion set-up as you head towards Elounda from Ag Nik.