You could calculate it by looking it up on the Tesco website - it says that the sachet is 25g, and it has 410 calories per 100g. So a sachet is 102.5 calories, which makes it just over 5 syns for the sachet, using the 1 syn per 20 calories rule for things with no free food content.
Ingredients are:
Potato Starch,Maltodextrin ,Vegetable Fat ,Salt ,Onions ,Sugar ,Rice Flour ,Whey Product ,Herbs (2.2%) (Parsley, Lovage, Rosemary, Chives) ,Yeast Extract ,Spices (1.4%) (Garlic, Nutmeg, Pepper, Paprika) ,Vegetable Oil ,Milk Fat ,Powdered Lemon Juice ,Flavouring