Ian,
From the Runway Edge Lighting Regulation 3515 (9) there appears to be a maximum but no minimum spacing, so I wonder if the WW2 spacing was the same, especially as the decoy airfield spacing was 100 metres, although in WW2, I would have expected measurements to be in yards not metres.
Part of the Runway Edge Lighting Regulation 3515 (9)
Be uniformly spaced in rows at intervals of not more than 60 metres for an instrument runway, and not more than 100 metres for a non-instrument runway.