Adrian, 

You could set up conditional visibility on the reference selectors so the user won't see the next dropdown until they have made a selection from the first one.

This would be the conditional visibility on the section:

And this would be the conditional visibility on the subsection:

Then the user would not see the section dropdown until the department was chosen:

Would an onchange microflow on the reference selectors work?  You could check validity of the selected values and set them to empty if needed.

Thanks for the reply Mike,

I do call an on-change microflow so that would be the place I guess to clear them down.

However, I don't know how you reference the entered value :( ... I did try this but it didn't work:

Alternatively, you could also set editability (and selectable options) dependable on whether or not a value has been entered?

As in: 2^nd dropdown is only editable when a value has been entered at the first dropdown, and similarly for the third.

I think your best option here is to restrict the selectable objects with a datasource microflow. So the user can't select an invalid value.

Additionally you can set up conditional visibility or editability, as suggested by Wieke and Nicholas.

Thanks for your inputs guys - much appreciated!

@ Mike - I'll have a look at doing that model sharing (to be honest I've not done that before so bear with me on that one). 

Making the drop-downs visible at the appropriate time is a cracking idea - thanks for that :)

Thanks for all the inputs guys - Much appreciated!

@ Mike I'll investigate the model sharing - not done it before so bear with.

Having the drop-downs visible at the appropriate time is a cracking idea, I'll try and put that in.

Again thanks for you help.

Regards

Adrian

Hi Guys,

Thanks for all your inputs - much appreciated.

I've added in the editable conditions and it works a dream!

Thank you all again! :)