Ruby rear screen drain channel

[Ilmoro]

My 1937 Ruby has the rear window drain channels fitted and intact but there are no connected drain tubes. Connecting the drain tubes is obviously a straightforward task.... But where do the tubes exit the rear quarter panel. I am assuming through the bottom of the panel or even the B post, but if this is the case my car appears to have no hole. Can anyone appraise me of where it should exit?

Thank you

Ian