Heater controls are dead easy. The facia is only held in with 4 clips, 2 top, 2 bottom. The bulbs are simple pull out and replace with the correct LEDs (Crazy LEDS on VVOC does them)
The dash is a little more complicated as getting it out takes time. If anyone wants a step by step guide I can write one up easy enough as i've had my dash out a few times. Once you get the clocks out though it's a simple case of replacing the old push + turn bulbs for some LEDs (again, see crazy leds). The rev counter/speedo takes 501 sidelight size bulbs but if you buy a kit from crazy leds he supplies everything you need. He does just about any colour you would like, including white, blue, red, green etc
My dash is done in half blue/half red to match my stereo, blue dials and heater with red MID/TID. I've also got blue LEDs in the door lights and rear grab handles but nice bright white in the centre light by the cubby hole and in the boot so I can see what I'm doing