Thanks Mulchman! I had discussed doing that very procedure (swapping coils around) to see if the issue follows potentially bad coils. I'll give this a go first. I'll do it this weekend and report how I get on.
One thing is for sure, if I can save $$$ by doing something myself, my wife will start talking to me again. The car has become a major source of contention!
In the meantime I will see what else I can glean from the forum by searching further.