My advice is not to deal with ultraleds.co.uk. I was very disappointed with their products and service. They removed my review of a product on the website as it was not favourable. The letter I wrote to them remains unanswered. I have informed Trading standards about the company.
I made my own about 4 years ago, punched four holes in the lid of a Walls Corneto cone, soldered together with a resistor and filled with epoxy, gives a brilliant light . LED are 3.4 volt high intensity and then cost from Maplin £4 each £1.20 for the ice cream and about one hour to make. the leds have shown slight uv damage but still visible about a mile off. Push pit mounted appears as a very bright star at sea level at that distance.