Thankyou you all for your valuable comments - to close the thread - I thought I'd throw out there what I did - it may be of use to members having not travelled this road yet. As you will recall I was faced with a heavily butchered intermediate gear linkage - ie: that linkage which sits to the side of the bell housing. Not only was the UJ worn but various roll pin insertions by PO's had left components seriously compromised and to make matters even worse, adjustment had finally been welded...
The story is pretty much explained by the photo's - purchase wise I had to buy some round bar, a 1/2" UNF turnbuckle and some 1/2" UNF left hand taps. (I had already purchased a replacement rose joint, the metalastic bush for the gearbox mount and an overhaul kit for the UJ).
I opted to move away from the norm in some areas, (if these prove not to work, then I'll simply revert back to accepted methods). The left and right hand 1/2" UNF threads either side of the UJ, are firmly located, (once adjustment is complete), by locknuts plus 3 grub screws to each. The rose joint is located by a threaded collar and locked by a single grub screw.
The left and right hand threaded studs were machined as a 0.002" interference fit into the salvaged UJ's, press fit, (they were tight..!!) and secondarily locked, (albeit I think unnecessarily), with roll pins. (Yes it would have been easier to weld these - but my welding skills require 10 minutes with a grinder for every 1 minute of welding....
)
The effective lengths of the front and rear control tubes were shortened in order to accommodate the extra length of threaded bar either side of the UJ.
A long way round? Maybe - but as one member of the forum said in another post "I just wanted to see if I could do it"