This technique applies to the steering tie rod ends on the MGA (and other cars). It can also apply to upper and lower suspension ball joints on other cars using that type of suspension.

DISASSEMBLING BALL-JOINT STUDS
You don't need a special tool to remove a ball-joint stud. Loosen the castellated nut several turns. Now all you need are two heavy ball-peen hammers of equal weight. Hold one hammer against the "ring" holding the ball joint stud, and strike the opposite side of the ring with the other hammer. A few hard blows should loosen the ball joint. Remove the castellated nut and take the stud out of its support.

This can also be done with a single hammer, about 2-pounds hammer works well. For this you need to hit the end of the steering arm straight on, using inertial mass of the suspension parts as the anvil. Preloading the parts in the direction of separation with a small pry bar may help. Theory is that the impact will force the hole slightly out of round breaking the friction bond on the tapered pin. John Twist has a nice video on this technique.

This method is not only relatively easy; it does not damage the rubber grease boot, important if the ball joint is to be reused. Caution: When removing upper or lower suspension ball joints (not MGA), follow the manufacturer's instructions for compressing springs to avoid injury.