The army bomb squad had to be called to the former Liverpool and Blackburn manager's house last July when undercover police scotched an attack on one of his neighbours.
A gang of thugs were planning to launch the British military grenade - which explodes into 1,800 lethal fragments - through the living room window of businessman John Ball.
Mr Ball was at home with his children aged nine and 17 months at the time.
The attack, which was abandoned when a security guard reported the men, would have been one of many intimidatory attacks on Mr Ball's properties and businesses.
On Monday, Liverpool Crown Court heard Mr Ball and his business partner Terry Riley were the victims of more than 20 attacks because of a venture involving a Liverpool garage.
Three men were said to have arranged the intended bombing of Mr Ball's home on 26 July in a bid to pressure him away from giving evidence in an impending court case against them.