please help new lawn weeds!

Hi this was seed not tuf and i laid it myself

 

Hi this was seed not tuf and i laid it myself

 

Hi this was seed not tuf and i laid it myself

 

Turf

 

Ive managed to get £55 in vouchers out of westland to spend on something to cure this problem.
I know i cant do this until next year due to new grass.
I want a product that will kill this not just keep it at bay!, but at the same time i dont want to harm my grass.
Any suggestions would be great.
Thanks

 

Oh and they said all there seed comes from america so could be why we nor they can identify the pest!!