I remembering reading somewhere that originally Nadia Rakovski’s number was to have been 9, but that the decision was taken to change her number to eight. This was due to the closeness of a former Number 9, a woman who betrayed Number 6 in ‘Arrival.’ So no doubt to have had Nadia as Number 9 would have seemed repetitive, seeing as she was also to betray Number 6. And yet it appears the information I once read was inaccurate, because recently I read in a copy of the original script for ‘The Chimes of Big Ben’ that Nadia’s number was originally to have been 7. So had that number been maintained in the episode, there would have been two Number 7’s in the village. Nadia as the Number 6’s new neighbour, the new Number 7, as for the old Number 7 he vacated the premises.
So why change Nadia’s number from 7 to 8, because as far as I can see there was no good reason for such a change. I cannot think of any good reason, not unless it was decided that someone who was to eventually betray Number 6 should not have a lucky number. And then to expunge 7 completely from the village, and thereby deliberately adding mystery to the affair as to there being no 7 in the village!
Be seeing you