Cascading Combobox And Dynamic Ranges?

I want to create a cascading combo box from some values that I have, ill explain how I approached it.

Cascading combo box is a combobox which values are obtained depending on the answer of a previous combo box.

So I set up a little table like so:

Categories Car Train Bike
Car Mercades First Honda
Train Ford Western Ducati
Bike Skoda Red Suzuki

and the combo boxes would be set aside from that.I collected the data in Named Ranges (A Range for Categories, A Range for Car, A Range for Train...)

The first data validation box contains = Categories the second data validation box contains =INDIRECT($C$2) (Where C2 was the range of the first validation box)

Once this was working, I decided to change the formula for the named ranges to allow me to add more values.

The formula was: =$F3$F8

I changed it to: =OFFSET($F$3,0,0,COUNTA($F3:$F96),1)

I expected this to work however, it just doesnt.... when clicking on the drop down arrow for the validation box, nothing happens. No box or values or dropdown.