Index: TD_Pre_Treatment/loader.py
===================================================================
diff -u -rabcf784299ec8c8617692b5a57cf286eea658b98 -rfc43fc2ed484aec6f49ef1c7f67a71c4d0d5d0d3
--- TD_Pre_Treatment/loader.py	(.../loader.py)	(revision abcf784299ec8c8617692b5a57cf286eea658b98)
+++ TD_Pre_Treatment/loader.py	(.../loader.py)	(revision fc43fc2ed484aec6f49ef1c7f67a71c4d0d5d0d3)
@@ -20,7 +20,8 @@
 # dialin
 from leahi_dialin.ui.td_messaging   import TD_Messaging
 
-from leahi_dialin.common.msg_defs import MsgIds, MsgFieldPositions
+from leahi_dialin.common.msg_ids    import MsgIds
+from leahi_dialin.common.constants  import MSG_HEADER_SIZE
 from leahi_dialin.protocols       import CAN
 from leahi_dialin.utils           import conversions
 
@@ -317,7 +318,7 @@
         @return: None
         """
         message = message['message']
-        self.index      = MsgFieldPositions.START_POS_FIELD_1
+        self.index      = MSG_HEADER_SIZE
         command         = self.getIntValue(message)
         commandString   = self.cmdStrings       [command]
         modality        = self.getIntValue(message)
@@ -350,7 +351,7 @@
         @return: None
         """
         message = message['message']
-        self.index = MsgFieldPositions.START_POS_FIELD_1
+        self.index = MSG_HEADER_SIZE
         self.lbFinalConfirmation                .setText(str(self.getIntValue(message)))
         self.lbTreatmentModality                .setText(str(self.getIntValue(message)))
         self.lbHDFTreatmentMode                 .setText(str(self.getIntValue(message)))