I have a lawn which totals about two thirds of an acre and, while the grass is good in most parts, fair sized sections are infested with a creeping weed with narrow leaves and thick, fibrous roots which become exposed after mowing or raking. I think (I'm not sure) this is Sagina procumbens, or "pearlwort". My soil is quite damp and some parts of my lawn become distinctly boggy in winter.
I want to know what weedkiller is likely to work on this issue, how it is applied, when and how much to apply, and where I can buy it in bulk to cover my large area. I live in southern Sweden, but I visit the UK regularly and I will be returning next in December - with my car and trailer - so I can buy some bags and bring it back with me to treat next year. Weedkillers in Sweden are outrageously expensive!
All advice gratefully received!

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