Bit late to deal with them now, so next year, treat in April with a Lawn Weed and Feed combination, and again 6 weeks later. Most are quite effective on daisies.

When I had a lawn, got rid when the children grew up as I hated mowing the darn thing, I used a selective, broad leaf weed killer, which there are many. As bamboo suggested you can get a weed and feed combination.

The one I found the best was Verdone. Interestingly, I read somewhere that it's actually a super fast fertiliser. The way it works is when you apply it, the liquid won't hold onto the blades of grass because of the upright angle. It forms on the broader leaves and flowers of the weeds, it's a hormone weed killer, it affects the growth hormone on broad leaved weeds, encouraging them to grow at a fast rate which they cannot sustain, causing the weeds to literally grow themselves to death! One application a year was enough to keep my lawn virtually weed free. The odd one that I came across just got a quick spray, so very safe for your doggie and kids if you have them?

Incidentally, I saw last week that my local B&Q store was selling their own branded version for half price, presumably to clear the shelves for Christmas things. I stocked up with some Miracle Grow, also discounted.