I grow my autumn fruiting raspberries in front of a native hedge. The grass in front of them is mown, which cuts off any suckers tempted to creep outwards into the grass, but otherwise, if they spread laterally, so much the better - plants for free!
I forgot to cut them down last winter, and as a result had a good crop in June on last years stems. I wondered if that would be it, but they are starting to crop again now, so I think for the future I will cut back half of them hard in the winter, and leave the rest - alternating which ones get cut each year. It seems to me that I will then get an almost continuous supply of raspberries through the summer and autumn.