Put water, crumbled stock cube and gelatine in a blender and mix 30 seconds or until well combined. Add drained chopped oysters, chopped shallots, sour cream, mayonnaise S+P and blend on high speed until smooth. Pour mixture into a serving dish and chill until set. Put extra mayonnaise, extra finely chopped shallots and parsley into a bowl. Mix well and spread evenly over the top of the pate. Refridgerate until ready to serve.