Tim, I really dont see the confusion. Im assuming that having posted the link above you took the time to read the meeting notes that it relates to ? If not I have pasted them below for you :

All robots(not ants) must carry at least one surface mounted non-filiment always-on lamp that illuminates when power is supplied to the robot(ie when the link is in) any colour is acceptable provided that it is in contrast to its surroundings. Suitable parts are leds availiable from Radio Spares(RS384-5020 series or similar)

Hopefully that will save you from wasting any money, it reccomends a part to use and it seems fairly explicit as to what is required. Another good LED to use is this RS part no. 376-9184

Ed
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