you will need to knock off the looses and replace with render then apply the pebble dash

Before you paint it, you will need to remove all the loose and blown parts, rerender and dash.
You should wait until warmer weather in the spring, its no good doing render or external painting in minus conditions.

waste of time painting it unless you strip of and repair the blown sections first.

Hackoff all loose areas then re-pebbledash then u can paint you can do it in cold conditions with the right additives and rapid cement.