Looks only like one IET diagram on the Cotswolds today instead of the booked two. Other is being covered by 165112.
Someone who, I believe, knows their stuff, posted on the GW Passengers Forum that only the workings listed below are booked to be IETs initially - so one diagram and a bit.
Also from next Tuesday the ‘proper’ diagrams start and the following trains are scheduled for a 5-car IET:
1W14, 06:54 PAD-GMV
1P25, 09:54 GMV-PAD
1W29, 14:21 PAD-WOF
1W33, 16:22 PAD-GMV
1P42, 17:26 WOF-PAD
1P47, 19:42 GMV-PAD
Not that GWR seem to have the trained crew available to manage to run these so far this week - 06.54 is cancelled past Oxford today for the second day running and the 16.22/19.42 is already showing as cancelled this afternoon, for the fourth day running.