Right, finally got these installed over the weekend. In the end I went with crash bars for the mounting location and had to replace my tatty crash bungs in the process. It was a pretty easy install after I had got all the parts I needed. Needs a little tidying up, I'll start with replacing all the white cable ties with black ones!
Here is the result before aiming and adjustment. The offside lamp is still a little lop sided although much less so than in the photo and is not so noticeable now. This is because the offside crash bar does not protrude as much and to compensate you must fix the mounts further outwards where there is a bend in the bar.
That night I went for a ride on the darkest roads I could find and honest to god, I have never been so gobsmacked by anything I have done to my bike so far. The output of these lights are amazing, better than the HID kit I had installed many times over. Even more impressive is that they do this whilst only drawing 15w each, about the same as an indicator. I was switching from highbeam only to highbeam with the spots and there is no comparison, I had to slow right down after I switched the spots off. The construction is very solid too, I don't need to worry about damage from knocks or water. My only worry is that they might be too bright for oncoming traffic if I don't switch them off in time.
To be honest I thought I had made a mistake spending so much on some lights but I am really impressed. I will get some night time shots asap.