Hello Folks
Posting this as it may help others. I have had the 830 and UT800 for a month or so and it works very well indeed. I had an RTL515 delivered yesterday and had a very frustrating 2 hours trying to get the light network to form . So frustrated that I had re boxed the RTL515 in order to return it. I thought I would have a final go today and tried deleting the UT800, adding the RTL515 as a light which then worked as both light and radar, but it all fell apart again as soon as I added the UT800. I had another thought - I also have a Garmin HRM strap sensor which was sitting on my desk so I put that on so it connected to the Edge830 and voila, everything works as it should! I had read another thread about someone having to make sure their speed sensor was connected to get the light network operating so it seems that if you have multiple sensors paired then at least one of them needs to be connected in addition to the lights.
It really shouldn't be that difficult....! Now I hope that it stays working when I go for a ride......
Cheers
Steve