hey sweet and doodles,
As you might know all Phd's divide their Phd in sub-parts, like different objectives etc...for a particular part of your phd may be an another prof could be experienced and well versed than your supervisor. so what i did was to i worked on the core areas with which my supervisor was well-versed and went to USA as a visiting research student to work with another guy who had more experience on that particular part. It helps if the guy you want to work is acquanited with your supervisor already!! and i hope most of researchers in the same area are quite acquainted. will give u more information if you are interested. bye for now and good luck. jc did u makie adecision