Hey rob, thanks for the answer, makes sense, methinks the rigidity of the whole system is my first problem, I have the old "hanging bolt" with Land Rover pipe clamp system and it is really stiff once all bolted up, not anywhere nearly as swingy as a td5 for example.
It is often (as you so correctly point out) not the primary problem but the secondary affects that cause the primary problem to keep coming up.
I have wrapped also wrapped my downpipes and Y junction with exhaust tape to keep heat off my starter, gearbox and trf case, this seems to work very well but I think the downside is that much greater heat differences will occur as the pipes stay hot inside their wrapping.
I need to pull my Y junction soon anyway to weld in a lambda sensor ( bought myself a mega squirt system from Hybrid from Hell)
So that will give me the opportunity to have all the bits in my hand and try solve the problem.
Rob, I am based in the south of Germany in a village called Heidenheim, sadly very far away from the landy centre of the world