The rules for drinking in cyclo-cross races have been clarified by UCI (and British Cycling).
Essentially you cannot be handed a bottle during a race but you can carry a bottle.
Below is the UCI clarification on this.
The Union Cycliste Internationale (UCI) acknowledges comments made about the rule change and wishes to clarify the following points. Riders may carry fluids on their bicycles and install bottles on their spare bicycles in the pit area. Hands-free water carrying systems such as backpacks are permitted, and riders may also carry water bottles in their jersey pockets. However, it is forbidden to receive a bottle from anybody along the course. Extra fluids can only be obtained during the race when a rider takes a spare bicycle, already equipped with a bottle, from the pit area. The UCI Cyclo-cross Commission will be following the matter very closely.
Commissaires at the Wessex league races will be advising riders of this ruling at races.