From Googling yes it appears to be relatively common problem as mentioned on Amazon reviews with issues with the left earpiece.
*Sigh.* I'm going to leave it over the weekend and log a claim with the Disputes Tribunal next week. I've over this, I just miss my headphones!!!
Thanks for your help everyone, I have a much better idea what to expect and as my communications have been via Email I have my work cut out for me documenting everything.
IMO and from my experience CGA doesn't seem to provide as much protection as we think, if retailers and manufacturers decide to just decline. This is because the consumer then has to take it further, and usually pay to go to the Disputes tribunal and waste all that time to do so. I had this problem for something worth $200, where the lenses on my polarised sunglasses started to go opaque in patches between the layers, and they claimed it failed due to misuse, when they couldn't provide any evidence of this nor did they do any testing. I also couldn't find any other examples of people who had had this problem, to reinforce my case. It wasn't worth it for me to take it to the TD due to the price, and they were a couple of years old, and it could a have gone either way, and I also no longer have my invoice for them which the retailer said I needed.
I am wondering why they consider 18 months is a reasonable life for headphones worth $500, if they have been well treated etc, and what they are basing that on?