Thanks a lot for all the advice guys.

Looking at the internals of the light, I totally agree that the main challenge is the optics that the light has to pass through.

Looking at the 20W versions with side directional beams, just a gimmic. That light wont reach the rings IMO, as they are connected via a single front beam.

So in the end, I decided that the 5W LEDSs that I had already were fine. They lasted 2 years. Only one has now packed up, so I have a spare - and they are half the price of the 20W (and a lot cheaper than they were when I bought them 2 years ago).

Thanks again. Cheers, Kev.