Daniel had been really busy & getting her over to him was a challenge, so I sucked it up & went back to see my local mechanic last week.  Didn't see Marco, but the boss said they would continue the challenge.  Booked her in for yesterday.  
Marco did the work again, swapped the original side/side shifter back in.  He apologised for not checking more thoroughly.  Same length, but there is a part of the original that is slightly adjustable, that wasn't on the replacement.
Picked her up yesterday afternoon.  Fully expected to have to pay for the labour, but the boss said no payment necessary.
And Marco's mood was much better having fixed the problem.
Took a looong way home just to be sure & took a drive this afternoon to our favourite spot, just to make doubly sure that everything was ok.......... she is now shifting like she should 
Feeling much better about continuing to let Marco work on her.