Whole fruit is syn free becasue you have to chew it and it you get full quicker. juices or smoothies contain high (natural) sugars from being broken down and you wont feel as full as you do when you eat the fruit whole.
Have a look in the back of your SW book as theres some syn values in there for fruit. Was the yogurt Fat free and syn free? and was the milk taken from your daily allowance? if not youll also have to syn these.