A couple of years ago, we purchased a new home with a 6m x 6m patch of newly
laid turf out the back. It was lovely.

2 years later, one corner of it (the sunniest) has broken out into leafy
weeds. I trimmed them with the mower (I keep it short) and have noticed the
weeds have grown underneath the lawn like a darn beanstalk! I have tried to
rip them up, have done most....

now - to regenerate.

What do I do? Douse the area in weedkiller and wait? When can I replant the
grass seeds?

Should I dig up the whole area with a ditch and refill it with potting mix?

If I could get an idea about how to go about it, would be most apprecaited.