There was one season where Gloucester were placed in the North division and Worcester in the South which struck me as especially bizarre.
Sounds like 2009-10 season.
Think Gloucester were playing at Cirencester that season having been flooded out from their Meadow Park home ground a few years previously.
The reason given was that Worcester City, despite being considerably further north than both Gloucester and for that matter Cirencester, were given a guarantee (
after being moved to the Conference South the previous year against their will after no Southern teams were relegated from the Conference National) that they would not be moved back to the North division for three seasons without their consent.
Worcester City refused to give such consent to an early move back to the North, thus forcing newly promoted Gloucester, who had just won the Southern League Premier Division play offs, to take their place.