So the YDK comes in 110 volt as well COOL you learn something new every day.
That deal with the motor housing seems like a good Idea.
You said "The previous owners solution to a clogged main intake tube (Irish setters I believe) was to remove the Pre-Filter ! That did wonders for the original motor."
The hepa filter , located under the cyclone housing on top of the motor would have gotten Packed with dirt and caused the motor to over heat.
Keep this clean and your motor will last a long time.
We get a lot of clients returning from there stay in the States with Dyson's in need of a 110 volt to 220 volt motor exchange.
I do believe from one of my sources that the Panasonic motor is less reliable than the YDK in any case