Axon 2.0 has suddenly started generating rafts below the build platten!! (on a rapman 3.1)

Hi all, no idea what we've done wrong, but our latest masterpiece has been stymied by the extruder nozzle trying to dig a groove in the upper bed, upon inspecting the bfb file in side view, it is apparent that the raft has been generated below the surface, really not ideal!!! - anybody else come across this? - have attached te build file in case anybody want to take a look - they're supposed to be vac. form patterns for christmas chocolate moulds...