There should be holes there. I expect there is a lot of rubbish blocking them. Lie on your back and poke them free.
I suppose you could drill a larger hole in the fibreglass bottom of the door, I can't see how it would cause a problem.
B spec. cars have a chrome trim next to the glass which can have a seal, but my A spec is like your's, no trim or seal and the rain just drains down into the door.
Yesterday at Shepton Mallet I noticed that an early A spec car had had the chrome trim and seal added to stop water getting into the doors.

On my first SP (A Spec) I too experienced water remaining inside the door. As stated there are (and should be) drain holes, however on my car there was a sealing rubber around the inner door edge, that on the bottom covered the drain holes, I pulled away and water came rushing out, I reaffixed the seal but cut away a gap for the drain hole. Water in the door is not a problem if it can get out, and not that I have really investigated a B spec chrome trim, but was not aware that there was much of a seal incorporated and had just assumed that the trim merely reduced the size of the opening to the environment.

Antony

AntonyB wrote: ↑Sun Feb 10, 2019 6:22 pm I have really investigated a B spec chrome trim, but was not aware that there was much of a seal incorporated and had just assumed that the trim merely reduced the size of the opening to the environment.
Antony

I think the seal was a separate addition.

On my 'C' spec. car the bottom seal between the door glass and the metal channel engaging the regulator incorporated a rubber flange projecting towards the outer door panel. When the window was fully raised it appeared that this flange was intended to butt against the lower surface of the window aperture in the door preventing direct ingress of rain. This was hardly going to be effective since there was nowhere for the water running down the window to escape to except over the ends of the seal and thus into the door.

As has been pointed out, there are water egress holes in the bottom of the door that should be regularly cleared of any accumulated debris. On original build the outer foam rubber door seals were fitted in sections leaving these holes unobstructed. When these seals are replaced it's important to ensure these clearances are maintained.

Have had a similar problem in the boot of the car. In this case, I drilled the boot floor but the hole often gets clogged up. Just as well we have fibreglass!

SimonP

Thanks everybody!