Had the head re-torque, oil changed and dyno'ed after my 1000k run-in period.
Prevoiusly, having fitted the FMF powerbomb header and rejetting the carb, the motor ws putting out 32.77 hp at the rear wheel.
Having now had the head ported and gas-flowed. it's putting out 37.23 hp - a 14% increase!

Torque has gone up from 31.75 nm to 33.93 nm - a 6% increase

I reckon for R1700, this has got the be the most cost-effective power increase around!
No added stress to the motor and no potential problems due to boring etc.
Now that I've had a chance to open her up - man, she pulls like a train!