An interesting little epilogue to this story....
When Suzuki agreed to replace the wiring loom on my bike they took two weeks to actually get one to Edinburgh. I called to try to speed them up and on the second call I lost my co0l slightly, pointing out firmly that I could have walked to their spares depot in Germany faster, etc, etc.
About a week after I got my bike back I received a letter from Suzuki GB apologising for the delay and giving me a "goodwill gesture" of £100 credit towards my next scheduled service.
It seems they do care after all! It doesn't make it all better but it has certainly made me feel a little more kindly towards Suzuki.