Dick calls Tommy by name despite the boy never telling him who he is.
Dick and Snowey get out of a lorry where they've been hiding and see a plane crash a good distance away. At the site is Anna and one of the villains. How would they have known where it was coming down?
The "two longs and a short" lighthouse flashes are clearly added in post-production, either by alternating darkened footage with undarkened (for the interior) or an overlaid 'blob' when seen outside.
(4:02) The dead Phillips is dragged feet first from the phone box he's just been shot in, but has to keep his head slightly raised to avoid it dragging on the wet floor (and also dislodging his hat).
(49:56) The edge of the boat the camera crew is filming the lighthouse from is visible at the bottom of the shot.