Hi guys, i work in a motor factors and also have a 306, if u open the bonnet and look on the right hand side towards the bulk head you'll see a plastic cover held down by torx screws, size T15, take that off, remove the housing and in it you'll see a filter, its the pollen or cabin filter, looks like a air filter, if thats filthy, change it coz that will affect the air conditioning, a lot of mechanics and garages never change it when doin a service, it should be changed every service as often as the other filters, it should hopefully solve the problem if the aircon still doesnt work after re-gassing it, them filters usually range between 7 to 11 pounds
Chris
August 2009