Clotted cream can be hard to find (and expensive) here in the US. Vicki uses the recipe below, and finds it works really well.
1 – 3oz pkg. cream cheese, softened
1 – Tbsp powdered sugar
1/2 tsp vanilla
1/2 cup whipping cream
Beat cream cheese until light and fluffy. Beat in sugar and vanilla. Gradually beat in enough cream to make a spreading consistency. Cover and chill 2 – 4 hours.