My take on the problem (using same unit as fred_ jb ) of the massive amounts of glare from the dials and illegibilty of the speedometer numbering on my 2014 GSA, this was just to see if it would work in this position and have little or no glare.
At the moment it consists of a couple of old GoPro mounts, as it seems to be fine I will leave the GoPro sticky pad and mount on the rear of the GPS speedo and make up an alloy mount that picks up on the rear of the BMW GPS mount.
I will also sort out a much shorter and waterproof USB lead and find some way of waterproofing the GPS Speedo whilst keeping it legible.
Neil, I haven't got round to fitting mine yet. If you lay it flat and use as maker intended what is the result on the bike's screen?