Cousin,
Not sure, but I was under the impression that if your base changed to the 'bus, or you went to a new base that was being set up with the bus (e.g. Dortmund) you got the rating with no extention to the bond. I would say, however, that you are correct in saying that if you volentarily transfer to a base with a different type, you'd get the new bond on top of the old. Out of interest, are any CTC cadets going straight onto the 319?
(Of yeah, flew KF the other day. 250hrs on the clock. Lovely!!)