While that is possible, your form would need some revision since some of the options are mutually exclusive - logic dictates that one wouldn't check both Yes/No boxes for the «Are you eligible to work in the UK?» question, for example - better to use a dropdown with Yes/No choices there.
For example, if your document employs formfields, you could use an AutoClose macro like the following in the 'ThisDocument' code module of your document:
Code:
Private Sub AutoClose()
Dim FFld As FormField, Cancel As Boolean: Cancel = False
With ActiveDocument
For Each FFld In .FormFields
With FFld
Select Case .Type
Case wdFieldFormTextInput: If Trim(.Result) = "" Then Cancel = True: Exit For
Case wdFieldFormDropDown: If .Result = "Choose" Then Cancel = True: Exit For
End Select
End With
Next
If Cancel = True Then
MsgBox "Please complete all the items"
.Saved = False
SendKeys "{ESC}"
End If
End With
End Sub
Using formfields rather than content controls and saving the document in the older .doc format will allow it to be supported on the widest range of Word installations, but the reliance on a macro - which any implementation will necessitate - means the safeguard is easily circumvented by those who don't allow Word to run macros or who use Open Office, for example.
For PC macro installation & usage instructions, see:
Installing Macros
For Mac macro installation & usage instructions, see:
Word:mac - Install a Macro