Tried Lehmanns and a few others without success - they were of the opinion spares would be difficult to obtan and costs would take this lens to write off point.
I wanted it repaired, so sourced the aperture flex and ring assembly from Hong Kong, and set about doing this myself on Saturday evening.
It took around 2 hours, of making lots of notes about how things came apart and went back together, and cleaning the lenses and connectors as I went along. I cant see the actual fault with the ribbon cable, I might test continuity on this to see if the cable itself is actually fractured. Total cost was £12 and two hours of my time. I have taken 100 test shots with the lens after repair and reassemby, just to ensure it is behaving as expected, and I cant complain. Previously i would have got an error at the point where I moved from wide angle to full zoom.