Hi,
Forgetting the issue of test flying, I thought it worth responding about building a new design.
The LAA does support amateur designers as part of it's organisational goals and there is evidence to suggest that it does deliver on that. Obviously though, to ask it to spend funds on investigating a design you have to be very committed yourself to stay the course and provide the necessary data to support the increasingly thorough review that gets carried out. If things go wrong, the lawyers will be all over them so don't expect a design to get signed off easily. I have been on the fringes of the process in trying to get a design approved that ultimately qualified as SSDR but I would warn you that it is not a trivial exercise.
Having said that, if you have a design that offers something special enough to warrant the work then you must contact LAA Engineering and have a discussion about it. There is no more effective way forward than that and contrary to the popular view, they will help you if you have a viable project.
Regards,
Colin