Turned out to be two bad solenoids.
The new one wss also failing to.engage. As soon as I replaced it with another one it started like a charm.
The reason for using the jumper cables was in order to short across the solenoid terminals I needed access to the terminals through the battery tray.
The problem is definitely something to do with the solenoid and not the starter. When I turn the key to start, the start solenoid clicks but the starter does not run.
As the solenoid is under the seat on the T210, I had do bypass the seat safety switch and extend the battery cables with...