Since its an Eniglish plate, the last letter will tell you what year it is. The UK started the "suffix" registration mark system in 1963. (So in 1963, your plate number would have been "123 4567A".) With "K" being the 11th letter in the alphabet, It should be a 1973. They based the suffix letter the year of build. They went to the "prefix" system in '83.

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