Dependent Combo Boxes

I have been struggling to figure out how to create 'Dependent Combo Boxe'. I know how to do this using Data Validation, but I can't work it out for 'Form Combo Boxes'.

I have my named ranges already set up and I have looked at various suggested VBA code, however, nothing I have tried works correctly.

My lists are fixed, so there is no need to have the flexibility to expand any of the lists. I simply want to have two form Combo Boxes, where the drop down list that appears in the second Combo Box, is governed by the option chosen by the user from the first Combo Box.

Is anyone able to help me with the relevant VBA code to allow this to work. I am a VBA novice, I can find my way around but am not very knowledgeable with VBA much beyond that, so any help would be greatly appreciated or if anyone has a simple working example, that I could look at, I would be very grateful.