Davina McCall can't explain her rosey outlook on life - admitting that the difficulties of her past may have pulled others down. The 57-year-old TV icon has been through many testing times over her years - including an addiction to heroin and more recently going into surgery for an emergency operation on her brain. The My Mum, Your Dad host alarmed fans this month when she revealed she needed emergency treatment after doctors discovered a benign brain tumour. She underwent surgery earlier this