Got your message. I have not come across your Grandad or Grandmother. However I have researched through "The Stage" publication and got lots of information on the Dench/Artaud/Whitfield actors. I think it goes back as far as the 1880s to the present day. However note that it is not free you have to subscribe to it. Good luck with your hunting and if I come across anything on your family I will come back to you.