Lets see services with not so good frequencies bunching:
Sv5 - 2 together
Sv34 - 2 together (today, 2 kubs)
Sv58 - 2 together
Sv59 - 2 together
Sv518 - 2 together, with 3rd one arriving in 5 mins
Sv966 - 2 together
and also
Sv9 - 3 together
Sv63 - 3 together
Sv291 - 4 together during PM Peak (St 32/33 direction)
961 can bunch quite frequently, especially when comparing
L113CRL and O405. there's a great difference in their top
speed...