Stone was a wrong 'un, no doubt. Heroin addict, with armed robbery, GBH, and attacking a policeman on his record. However, it's a almighty jump to then commit this heinous crime. The paper thin evidence is supported by Josie saying he asked for money initially, and linking that to his drug habit, but the prosecution said he was there to steal lawnmowers from people's gardens. If he was there just to thieve, why would he target a family walking home from school in the country? Best he could of got was maybe £10-£20. Don't buy it. The guilty man only wanted to kill. That was the ONLY motivation here. Josie described the perputator as a tall man, Stone is 5'8 and the e-fits and witness descriptions of the man in the beige car talked of a cherubic man, + Stone didn't own a beige car.
Not convinced it's Bellfield, as it doesn't match his previous crimes, but it wasn't Stone.