Good day.An A/C gas leak is very common in Prados mainly the cause will be the evaporator which is located under the dashbord that is why you need a good shop to do that.You can try AC Delco garage as they are considered one of the best in Doha,plus that the same job was done to one of my friends Prado at the same shop and it was a very good one.There is one AC Delco at Salwa road near Tayseer petrol station (this is the main) and the other one is at the main airport road at the same line of Rawnaq and Rameez shops.Good luck