... removed (the surround is cut from an old Metro blanking plate to cover up a mass of holes a PO had drilled around the edge of the opening):
And the modified blanking plate ...
CD player with cassette adapter:
Factory mono speaker baffle:
Maybe some artistic licence in this drawing as it doesn't seem to match up:
77 (America) and 78 (UK) factory speaker cable routing, showing the grommet in the panel between door space and cabin ...
... and in the end of the door casing. I've used similar routing for the central locking in my 75 V8. This had the holes in the door casing already, with a sealing grommet, but I fed the cable through the hinge as I didn't want to drill a visible hole, not knowing this routing at the time: