This would be 1960's [ late 1960's ] looking at the Pumps - rather squat compared with the pumps of the 1950's and earlier.
Looks like 83 Octane on the standard pump - Boron - was it a bit more.
Cortina seems to have the Black base number plate so at least 1964 on and the model came out in originally around 1962.

Name:  McLaren #055 McLaren Service Station Remuera - Caltex 83 Boron Marfak 1960's arch Barry Murray .jpg
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An Advert / Article on McLaren [ Elva ] - from the Can-Am era - 1968.

Name:  McLaren #098 McLaren Elva advert 1968 arch Clarke Walker.jpg
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