Parts needed are:
Mmi trim from a5
(beware of different screen size).
Drivers side air vent surround from a5.
Dash clocks from a5.
Tools required are:
T15 torx screwdriver
8mm socket and extension.
Trim pry tool.
Paint if your changing colour.
First off you need to remove the trim from your car. Loads of guides on YouTube etc so I'm not going into detail.
Once both trims are off you need to remove the clocks. They are held in with 3 8mm bolts. One in the bottom middle is hidden so you will need to lower the steering.
You may need to unclip the trim over the steering column that has the leather on it. It just pulls out.
Unplug the clocks and remove.
Next you need to strip down both sets of clocks. Remove all the torx screws. Unclip all the trim and remove the bezel and then the screen. You should be left with just the black base trim of the clocks with the workings intact.
This is a good time to polish the screen if you want.
Once you have both stripped down (don't mix them up) start with your original a4 clocks. Put the a5 screen and buttons then the bezel. Clip and screw everything back together. Put back in the car and plug in and bolt back in place.
Refit the steering column cover and then the a5 trims. Should all fit with no problems.
Few pictures of mine finished. I also had the trim painted in metallic gloss black along with the center console trim and the door inserts.
Parts cost me about 60 quid. Clocks were 40. Trim was 20. Paint was extra.