Similarly, the BS1363 standard has been updated in more recent years, not to change the overall plug configuration but to add things like the sleeved line/neutral pins (the plug shown on that 1947 page is a relatively new one).
I can't work out the seven connectors referred to there. If the 3-pin 15A was still specified, what was the odd extra one? If 3-pin 15A had already been dropped, then we're two short.
