Derby Sun Roof drains

[jaz36]

New member 1936 Derby 4 1/4 B176HK. Currently replacing windscreen and while headlining removed examining sun roof drains. Metal pipes appear to have been replaced with plastic in an earlier restoration (now requiring repair) but correct configuration difficult to fathom. Current drainage directed to cowls fitted to front upper corners of coachwork, but suspect these to be retro fitted. Did the original design drain through the front door pillar? Looking at pictures of the Derby not many have these cowled outlets.