Originally Posted by J Brough
......... The shop is very respected and reliable, so it is hard to believe that the balance is off, but mistakes do happen......

Have you brought the car to the shop?
A quick demonstration of the vibration might get some address by them.
I'd expect a properly balanced rotating assembly should not be the source.
Do you have a magnet oil drain plug, or have cut open an oil filter to see if there is any obvious bearing or other metal showing up?