I think you new weed is a type clover 28, WE have it down here and it can overpower some grasses.
Grazon will kill it and not your grass..
Still it's nice and green and stopping dust so maybe it's a good thing in your spot.

Managed to pick up 33mm this morning from a nice damp day and night. Might chuck a few handfulls of dynamic lifter about the gardens
even with more rain forecast later in the week it will do some good before it all washes away.


Cheers