Bryan Bateman wrote:
At my club here in the UK, uke's are chosen by the grading panel on the day. When I was living in Japan, uke is chosen by the dojo cho, but chosen in advance so that you can work with them for a week or two leading up to the grading. Either way, you have no choice in uke's.
At our mother-dojo in Japan, like here, uke is determined in advance by the Sensei (how far in advance is the only variable).