Seed savers in Clare and fruit hill farms in Cork will both have white clover seed by mail order. You are looking for an evergreen, winter hardy white clover variety. You need to clear the ground first. There are a few options on this, some of which are quite alternative and all of which may take a little time, but worth the effort to treat your land with respect and kindness rather than kill it off with chemicals
1. You can cover the existing lawn with heavy card/black plastic for a while to kill it off by removing sunlight..
2. If you can borrow or invest in some chickens in a moveable enclosure. They will scratch everything off the soil pretty quickly and then you can move them on to the next spot while you sow clover where they just were.
3. You can borrow a pig to remove all vegetation if you can pen it in proper;y with a temporary battery powered electric fence.
4. You can rotavate it and prepare it if you are not willing to wait, however I always feel this is a very invasive method which kills the micro life in the soil.
5. You can spray it with vinegar, on a dry day in the growing seasons, 3 times in 24 hours. Distilled white vinegar, with a squirt of Castille soap or eco-friendly wash up liquid.
Once you have bare soil, you need to prepare a fine seed tilth as clover is fussy enough. The clover seed is very fine so you may need to mix it in with some horticultural sand in order to throw the seed out by hand evenly.
Clover can only be sown between May and October as the soil temperature needs to be quite high to make this seed germinate.
It takes up to 6 weeks to germinate so patience is required.Keep off it and set up sprinkler system if we have a drought to encourage germination.
Once its roots seem strong enough, start mowing it at a high setting first , then a week later at a lower setting and onwards until the plant is forced to grow horizontally and become a thick carpet.
Clover may need reseeding every three years if the carpet is not coaxed into a thick knit. These second or consequent seedlings can be done by cutting the existing clover sward, scarifying it and sowing the seed into the exposed soil.