Sorry.. weekend was so busy I had to neglect everything else. I wouldn't expect the Lucas to be related to the no-start problem; it ran fine with the Lucas before changing the filter?
If it won't start it's almost certainly because there's trapped air preventing the pumps from injecting diesel into the cylinders. My suggestion is to run the manual prime lever a while longer, test again whether it starts, and if not then proceed to bleed the air from the injector lines. Summarizing what's already written on that: loosen the nut and crank the engine. You should be able to see the change as bubbles decrease, wetness increases, and spray distance increases as the air is bled from each line.
Edit: odd coincidence... a rental customer showed up a few minutes ago with the towable air compressor with the Deutz engine I've mentioned here a few times. Said it wouldn't start this morning. After a couple minutes of troubleshooting I asked whether it might have been run out of fuel. He said it had gotten pretty low, but the tank wasn't dry when he re-fueled... so I grabbed a wrench and proceeded to bleed air from the injection system just in case. Sure enough, that was it. After just a few cranks with the #1 tube loosened it started stumbling and sputtering. I had to run the starter a few more times as I continued bleeding injectors #2 and #3, then another pass through them all just to be sure, but it was probably 5 minutes total from beginning the bleeding to engine purring like normal.