I decided that as all my interior is blue along with the electronic stuff, that I'd fit blue leds to the dash. First attempt. There's not enough light spread to light up the needles properly and also the resistors that are fitted are to small in value. The leds kept failing after about a week or two.
So after a rethink I fitted white leds (which are closer to the blue spectrum than normal filament bulbs) in blue holders with the correct value resistors (620ohms).
Much better. You can't tell from the photo very well as the camera corrects the blue hue somewhat. But suffice to say it's better and blue.