If you want to apply conditional validation on 'AudioVisualRecording GRid' or 'Photograph GRid' then you need to add this input to 'A12425GABC1234002M'.
{{digitalinfoForm.controls?.soundRecordingGrid?.errors?.grid.message}}
If you want to apply conditional validation on 'Photograph GRid' then you need to add 'SoundRecording GRid' field input to 'A12425GABC1234002M'.
Conditional Expression with type 'string'
{{digitalinfoForm.controls?.photographGrid?.errors?.grid.message}}