no point in trapping/shooting/bleaching the rat you see unless you take away the benefits to the rat of being there.... control food waste, clear shelter and so on. I keep my garden reasonably rat free by limiting how I feed the birds, beating round the overgrown corners of my garden, sheds and garage and being really careful about how I store and dispose of rubbish. You can get rid of one rat as often as you like but if the food and shelter remain, others will move in. Of course with the current quiet streets and so on and the lack of a food supply from shops, rats, foxes and so on will be getting bolder.