After surfing around for a set of 2" risers I found these at Chainspeed......http://chainspeed.co.uk/products/helibars-tour-performance-handlebar-risers-for-kawasaki-concours14.html
1" and 1" & half are easy to find, but after advice from PRD I went for the 2" ones.
I collected them yesterday as Chainspeed is a 20 mins drive from home, they do keep in a good stock so for anyone thinking about a set, try them.