Ok. My mate James tells me these new USA made rods, which are a blend of aluminum, copper, magnesium and zinc, have a Brinell hardness of 100, and if used properly are stronger then the ally. Will order some this week.
Already thinking I can have another crack at making a new foot rod for the brain cartridge, as it can be in sections and not a 200mm long 8mm diameter piece that flexed when I looked at it.
All of my planned joins would be fresh out of the lathe and devoid of any oxidisation and should not a drama.