Some thoughts re Wigan situation
1) if I recall correctly the "one from the north, one from the south" rule only applied for 2 or 3 years at the ned of the seventies and even then it was scuppered one season when Wycombe (Isthmian league) also applied.
2) I am not sure we were a bigger club tha Wigan through the 60's and 70's. OK, they won the NPL "only" twice - two more times than we did - I would say biggest Northern non league club was Macc 68 -72 and Boston 72-77, with us claiming the crown 65-67 and 79 -82. One of the main reasons Wigan finally got in was they got to FAC3 and put up a creditable performance in loisng 0-4 at St Andrews (injustice!0
3) There was a view at the time of the Rochdale fiasco that some league clubs were unwilling to allow a non league club in as that woudl make 3 years in a row - Wimbledon, Wigan and us - so injustice again!
4) I remember many of the older Alty fans in the 60's and 70's beleiving Wigans ongoing applications were doomed beacuse of the Wigan Borough scandal in the 1930's (resigned fromthe league mid season, record expunged) and the fact that Wigan Athletic inherited their ground on their formation the following season (i.e. they were the same club under a different name). I also heard that they had appiled to the Scottish League in reaction to this FL embargo.