Just to update this call, my issue with switching flavors was due to amending scripts which already had switch flavors in.
When I amended them I had to put the GUID in, which was fine in the source system, but because as Chinthan and Tamas both mentioned the GUID for each flavor will change if you import and export them, the switch flavor subsequently failed in the target system.
To resolve this I removed the flavors from the target system, created a transport fro all these flavors, and transported them to the target system, so all works fine now.
Thanks again to Tamas and Chinthan for setting me straight with this issue.
thanks,
Ian