I ran across someone that wrote "I have a nexus s, I am fairly pleased with it. But the headset that Samsung provided with it is fairly bobbins." Needless to say, the first thought I had was WTF THIS GUY MUST BE BRITISH. Was that a wrong assumption?
I've never heard anyone use that expression either, but a quick google search returned this: http://www.urbandictionary.com/define.php?term=bobbins For a term that I've never heard in my whole life it sure does have a lot of definitions.
Fairly bobbins just means it's fairly rubbish; like total bobbins means it's total rubbish. I'm not sure why you twos haven't heard it. Maybe you're illegal immigants or somethink.