Got a laser/ infra red thermometer which has given the results so I think the RHS cylinder is running at nearly half the temp of the left. Will read temps again as per your instructions and record the results.
Will also disconnect the lambda's and see what happens (obviously with the gizmo set at zero or removed).
There is the Problem Right there !! It should be running within say 20 degrees of the other chamber
Why is it running half temp Is the Next question you want answered
Do Not remove Spoofer
Change nothing else !!
Just Disconnect the Lamda's
And test again
If no change? Do a Compression test Before you do anything else!!
If you have a large variance between the sides?
Recheck valve clearances, Rotate the engine in the normal direction of rotation with the rockers covers off
Watch the Inlet valves Open and then close and use a 10mm wooden dowel in through main the plug hole to verify your TDC position and Set the rocker end float and
then the rocker arm to valve clearances on that side
Remember to rotate the engine just short of one full turn watching the inlet valves on the other side close and then verify that you are at TDC with the dowel in that plug hole and do the other side
If you have reasonable compression between cylinders ???
Move Items from Right cylinder to left cylinder ONE AT A TIME
if the temperature fault moves to the other cylinder ???
The last thing you moved is faulty
Stick coils Upper first then if no change leave the 2 main ones in there