John Rowland ) gurgled happily,
sounding much like they were saying :

The 253 used to always come in bunches of seven. I was told this by
someone, and I experienced it myself. Given that the old 253 was
effectively two overlapping routes, this isn't too surprising,
although 6 might be more expected.

Only because it's difficult for groups of three-and-a-half buses to arrive
simultaneously.