Hi BW,
Thanks for your reply, good to hear that it is not a common problem. I think it is probably due to the weld why the A arm had this fatigue crack. I dont have shaft bind now but indeed it could have done so in the past wrt joules's comment. I own the car now for a about a year, so do not have much on the history other than what I have found out so far...My RH lower A arm is good although it shows signs of jacking on the a arm .
In the mean time, I have made a repair of the arm by (mig)welding and adding some extra (sheet)material = thickness, thus lowering the tension levels. Will monitor it over the coming months but for the short term it should be ok.