Thanks for the advice Andy, but I've got tons of sockets, like for 1/4", 3/8" & 1/2" I have single and double hex shallow and deep sockets, in 3/4" drive its just shallow single hex, and air impact guns for 1/4", 3/8", 1/2" & 3/4", and a dewalt cordless 1/2". I do agree that impact guns are game changers. However, because the bottom balljoint comes in from the bottom of the wishbone and the nut is very close to the underside of the driveshaft's outer CV joint as it enters the hub, all you can get in there on to the nut with is an open end spanner.
I might get a ringkey over it it I skimmed it with a grinder to make the ring thinner so it can get between the nut and the CV joint, or if I cut the balljoint off the wishbone, and removed the hub with balljoint still attached to hub then I could get a socket on it and rattle gun it off, or slice it off as I like playing with the powertools, but rattle gunning it off would be the more sensible solution as it would then leave the pin intact and give me somethin for the balljoint splitter to press down on.
If you mind the pictures of my driveshafts earlier, where you suggested I find a parking space that wasn't in the north sea, the bottom balljoints threads are like that as well, so between the size of it, the inherent torque, compounded by 18 years of scottish rusting, its taking way more force than an open ender is able to exert.