The good news is that there has been some, the bad news is that the outcome doesn't meet all the requirements for a commercial drive.
Let me explain.
The prototype gear box was made with cut gears, which were expensive and we had to look for alternatives. A Chinese manufacturer said they could produce what we wanted by printing the gears on their machines. After a prolonged period of exchanges this turned out not to be the case.
We went and looked elsewhere and a different prototype designed for P4 is in the process of being brought to market using printed gears. The bad news is that they will be sold with the proviso that the gears are not designed for sustained running, which is not what I wanted.
This is a problem that money could make go away, but I fear that he market is so small that the money required is far beyond my means. Rough ball park figures of around £10,000, or $15,000. This would probably mean producing 10,000 sets of gears to get the unit costs down.
So the project is now on hold until we can come up with alternatives.