Have you considered getting in touch with the local library that covers this area? You could ask them if they have electoral rolls for 1950 and if they do, could they tell you who was living at the property.
They may make a charge for this.
If John was a child at the time he won't appear as the electoral roll only listed those eligible to vote.
Do you not know the name of the family or John's surname/probable age in 1950?
