I have done this before.
It goes as follows:
Remove stereo/pull fascia forward and disconnect stereo and other plugs - Hazards/door lock
Place to one side
Spot your target, the heating controls, they're held in by two Torx T20 bolts on either side
Undo these and store safely
Now the tricky fun part
Push the heater control backwards so it unclips from the dash - you'll see the white peg clips above where you've just taken the bolts from
Now start to wiggle, shake, rattle and roll and eventually it'll come free - you'll be pushing the heater control cables back/forth so expect some resistance
Another tricky fun part once you have the dial controls in your hand - small flat bladed screwdrivers need to be inserted all around to remove the front black fascia, giving you access to the internally mounted bulbs
And voila!
Replace bulbs
Refitting is reversal of removal!
Enjoy!!