I brought these from argos and sadly didn't keep the receipt [I just assume things will work for a long period of time.
they where most definately the best in-earphones I have ever brought, but £25+ is not worth it. I noticed after two weeks of use [at least 3-4 hours a day 5 days a week]that the sound wasn't as excellent as it first was, then last week the right sides bass boost busted. So when they are on, you get a nice rich base tone with excellent treble on the left while the right just plays the treble, it's listenable unless you are really into rock and generally bass-y stuff.
the most annoying thing now is that since the the right sides bass has gone, I get a constant whistling noise. The earphone has a bass hole for some soundto come out to counter act outside noise, so now whenever they are on outside the wind makes them whistle.
although these are really really good, when they are in good working order. If you buy these make sure you can get a replacement if they break.
I did feel in large part I paid £[...] for gold connectors, which to be honest don't make a difference.