SSRS Matrix Categories with no data

Hi,

I have a dataset as below in SSRS, without a category 1 or category 3 for customer 2 but I need to show all categories for all customers. This would show as £0.00 sales even though the category is not in the dataset for that specific customer. 

Is there a way to do this and almost list a distinct list of categories from the overall dataset, but for each customer regardless if its on that row of the dataset?

Thankyou

Liam