METAR for 11:20 shows wind at BOH 180 degrees 19 kts gusting 46kts. Almost straight across runway 26.
SOU at 11:20 160 degrees 12 kts gusting 23 kts. Much less windy and little crosswind on runway 20.
I'm sure the wind at BOH was the cause of the diversion. Why it diverted to LGW and not SOU is another question.