I'm a 17.5 stone, size 12, tall, dog runner with a history of bad knees that has reduced me to running as my only sport! I currently run in old style Saucony Omni Grid which have spared my knees. Unfortunately, their grip is not brilliant in the mud. I've tried specialist running shops around Leeds but they've not been much help. I don't fit into a size 12 Asics. Can anyone suggest anything suitable for an old plodder?