I forwarded the problem on to the PAB...
After a good hour of passionate debate, held over a really nice lunch paid for out of my membership fees, they couldn't come up with an answer that took account of the wider stakeholder community.
They have therefore formed a sub-committe that will produce a paper on the matter for discussion at the PAB meeting to be held in January 2009.
On the plus side, Rob says that the salmon & cucumber sandwiches were "simply divine love".