My 09 Panda Dynamic 1.2 clearly had quite a lot of air in the cooling system after the cambelt and water pump were replaced, very apparent with gurgling and sloshing noises coming from the heater matrix - I made matters worse by thinking I could just bleed the air out from the plastic thumbscrew on the heater pipe, which plainly did not work. Reading this thread galvanised me to do something about the air, to avoid any risk of head overheating.
A local Alfa mechanic suggested that physically blowing into the expansion tank can help to drive the air out of the system. That's plainly a non-starter because on my car the expansion tank is part of the radiator, so not very accessible! Then, I wondered if I could somehow adapt my Gunsons Eezibleed kit to pressurise the cooling system via the expansion tank filler, and allow the trapped air to be simply released. After a bit of experimentation this actually worked a treat, with most of the air coming out of the heater pipe bleed screw at the first attempt, and the car on level ground. The Eezibleed cap has to be held down firmly to seal effectively onto the expansion tank filler because the threads are not compatible, but a second bleed attempt with an obliging friend holding the Eezibleed cap down while I fiddled with bleed screws was a total success, hopefully permanent. I might get a suitable drilled rubber bung to use with the Eezibleed kit in future. Please note that I did make sure to fully clear out any DOT4 residue from the Eezibleed kit before I did any of this, and then rinsed it clean and dried it afterwards.
So, a good outcome for me, and hopefully useful for anyone else struggling to bleed air from the Panda cooling system.