Thanks for all the helpful words and pictures here. Just done my Fabia resistor pack. Only tips to add would be:
1. I stuffed some rag into the apertures below the three Torx screws holding the airbag unit in place to prevent dropping them. Not having a magnetic bit I made a wire loop to pull each screw against the bit when removing and replacing, again to avoid dropping them.
2. Having removed the three Torx screws , use a nylon trim removal tool to prise up the cover from the top of the dashboard. (Like the screwdriver is shown being used in the above video - thanks foundsound - but a trim tool won't do any damage.) It's the cover lugs which are preventing the airbag unit from being pushed out from below, so that becomes very easy.
3. I wore gloves when delving into the resistor area as the adjacent metal frame is very sharp.
4. Skoda manual says to switch ignition on before reconnecting battery earth lead. This avoids having anyone in the car when the ignition is made live again in case the airbag goes off at that point.
5. Test all the fan speeds now work before reassembling anything. (If the airbag is still disconnected you'll get an airbag error code which has to be erased. Check that does erase permanently before reinstalling the airbag.)