I'm not sure any of the IET services will call at Tackley, Heyford or Kings Sutton in regular service. The test runs may well have checked stepping distances, clearances and confirmed the SDO requirements at the intermediate stops, but that doesn't mean trains will be timetabled to call.
The Oxford<>Banbury IETs from December are scheduled to be:
06:20 PAD-BAN (arriving 07:35)
07:47 BAN-PAD
18:28 PAD-BAN (arriving 19:35)
19:46 BAN-PAD
The timing of the down services indicates they won't be stopping between Oxford and Banbury, certainly not the evening one anyway, though I'm not completely sure about the up services.
The Oxford<>Banbury IETs from December are scheduled to be:
06:20 PAD-BAN (arriving 07:35)
07:47 BAN-PAD
18:28 PAD-BAN (arriving 19:35)
19:46 BAN-PAD
The timing of the down services indicates they won't be stopping between Oxford and Banbury, certainly not the evening one anyway, though I'm not completely sure about the up services.