Yes, I have seen this and tried it myself.
In this instance, the file also has long/lat data and the points are actually posted using these geometry fields rather than the postcode data.
I would like to find a way of plotting data without the long/lat and only postcode data.
I have tried:
changing column name;
splitting the column to use only the first half of the postcode - this worked but not enough detail;
trying all the geographic references given in the Local Data File posted by The Information Lab.
Still no joy.
Any other ideas?