Thanks Frank.
I finally got a Round Tuit, and here is the relevant piece from the Race Manual (Issue 2: Update for 2017 Racers
):
EquipmentAny standard commercially available upright bike is permitted with reasonable personal modifications.
This is, however, a race so we want riders to have a fair and comparable equipment baseline for a
credible athletic and strategic competition. Equipment should not provide such a dividing line in
performance such that there is no reasonable comparison of two rider’s efforts. It is for this reason that
tandems and recumbents and other out of class machines will not be classified on GC (General
Classification) unless they allow a rider to compete on par with the efforts of other able-bodied riders
where they would not normally be able to do so. Where registrations for the race exceed capacity riders
we will not be able to accept riders who cannot be classified on GC.
These rules are by no means exhaustive and may be annexed in future updates.
(So it seems that tandems and recumbents are in the same boat
As you say, unlikely to be allowed without a change to this reg.)