I can personally recommend Jose to transfer from Faro to Isla Canela. He lives in Ayamonte and charges 70 euros each way. He also does local excursions and shorter taxi rides around town. You can text him in English on 0034 615934066I Just tell him you are staying at Sarahs apartment at Isla Canela and ask if he can fit you in.
He will meet you outside arrivals at the airport and drop you at the front gates of the apartment on the beach side.
When arriving many drivers will drive you in through these secure gates into the car park at the rear of the property. You will need to press the button on the electronic key fob for the gates to open. If they fail to open you can use the pedestrian gate key (on the keys provided) to open the foot gate. You will see a black short pole with a light switch style button on it. If you press this the gates will open.