Galloping into her twilight years, 45-year-old Roana is the UK’s oldest horse. Ageing is neigh problem for the mixed breed mare , who has already far exceeded the average 25 to 30 year equine life expectancy. And this old nag shows no sign of slowing to a trot, according to her owner Cerys Brown, 37, who puts her long life and happiness down to her daily Mars bar! "Roana will do anything for a Stud Muffin horse treat or Mars bar!" she laughs. Just five when she first took riding lessons at the