Rats live where there is a good food supply and somewhere to raise their young. Remove the food and safe environment and they will find somewhere to live. Just make sure any out buildings and the house are vermin proof and remove the compost heap completely, dig the well rotted stuff into the garden, get rid of any waste not composted and don't put new stuff out.
Rake out the dead vegetation from the hedgerow and generally clean up the site, burn it or take it to the tip. Any food left out for birds etc will also encourage vermin.
If the problem persists your options are limited to pest control. I don't know of any operators that live trap rats for release elsewere.
Tinker
March 2009
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