I suspect that the system you refer to will attempt to direct as much airflow as possible under the roof panel to create negative lift, and have some kind of spoiler to the perimeter of the upper surface to disrupt the airflow and form eddy currents(sorry eddy!!)and therefore prevent laminar flow or suction. Sorry to hear the installers don't want to play ball, but I do understand your wish to get a local sparky to fit, however I understand that to get the FIT benefits the panels and installer need to be MGCS (or whatever) registered. When I looked into it about a year ago I came to the conclusion that payback would be about 6 years and as I was 70, could not decide if it was worth it!!! G.