The only ones I can see in the Maplin's catalogue at 20mA or below are 5mm extreme brightness @ 50p each, or 5mm standard violet or turquoise @ £2.50 each!
Perhaps limiting resistors or 2 LEDs in series might be the answer - I've just had an exciting few minutes on my breadboard and 2 LED's in series drop the current! (I told you that I am a newbie )
With the two leds in series on the breadboard how were they connected and what series resistor.?