Most councils dont have pest control dept anymore, & have contacted it out to commercial firms who charge extortionate fees for it. The best poison is that sold through agricultural suppliers in 4 kg tubs BUT you need a licence to buy this stuff so only available to farmers and other licenced users. To get a licence you have to attend a day course on how to use it.The stuff they sell in small packs in garden centres etc is less potent stuff. Might kill a few mice but little or no effect on large rats.