Dependant data validation list is empty when spreadsheet is first opened

Hi Excel gurus,

I wonder whether anyone could help me, I have set-up a dependant data validation lookup with a Main Category and then 2 levels of sub-categories. Unfortunately the sub-categories had to be set-up with numbers at the beginning which restricted how I could set-up the dependant data validation drop-downs with Excel not allowing named ranges starting with a number. I have set-up this dependant list with help from Jerry Beaucaire's site.

The solution I have does work but on the second sub-category level it only shows the drop-down values if I go into the Data Validation menu in Excel and click the OK button (without changing anything). Everything works fine from there on.

I have attached a stripped down example of my file and I've copied out the formulas I have already in the data validation. I only get the problem with the second sub-category, not the first one, but I can't see how to modify the second formula and for it to still work.

Any thoughts gratefully received,

Mark