nigel Ive been runing slightly higher tyre presure 2psi both ends , I dont get any shudering, check your disks arnt warped ,or your fork shilds arnt binding , sounds like somethings not rite.
Find nothing wrong with the front suspension myself , push it pretty hard with heavy braking etc . Enough to wear front tyre and pads out in under 7000 miles .
I fitted progressivley wound springs on my last bike, Harley Fatboy, and it made a huge differnce under braking - bike would settle into the tarmac instead of the front end diving.
I will be doing the same on the RIII as soon as I take the forks off for painting - probably during the winter.