McDonalds Grey Owl (Cnr Old Johannesburg & Brakfontein Roads)

I am a regular customer of McDonalds and find the overall experience pleasant. I buy Chocolate Milkshake almost weekly and every time I bought one at this particular branch, it is not close to he shakes sold at the other branches. It is like a watered down Vanilla shake with a bit of colour. On Monday evening I bought one again at the mentioned branch and told them when I placed the order, that if the shake was not as the shakes of the other branches. The shake was the same dull, tasteless product. I told the attendant I am not going to accept this and they replaced it with a Strawberry Shake. Even worse. I spoke to the manager at the branch ans she told me that they are a new branch and have electronic machinery that automatically add the syrup. I am not sure if this is true or if this is a way to try and save money at the client's expense. I bought shakes at other outlets after that and they were all how it should be. A rich, creamy chocolate tasting shake - as expected. Please look into this, because this leaves a bad taste in ones mouth - trying to con the customer with an inferior product.