I used George Meyer AV in Los Angeles to modify my Krell gear to UK standard. Quick turnaround, although it is across the country for you. They are Krell factory Authorized repair center.
Also, you are spot on not wanting to use a (Step-Up) transformer. They introduce noise in to the system, as well as add to the utility bill, which, in the Uk are much higher than the states.
Hope this helps.