It looks like another attempt at a Wolverton swap is to be made tomorrow;
5Q81 0633 Wolverton Centre Sidings to St Philips Mrsh H S T D
Real-time train running information for 5Q81 0633 departure from Wolverton Centre Sidings to St Philips Mrsh H S T D on 20/09/2023. From Realtime Trains, an independent source of train running info for Great Britain.
www.realtimetrains.co.uk
5Q70 1331 St Philips Mrsh H S T D to Wolverton Centre Sidings
Real-time train running information for 5Q70 1331 departure from St Philips Mrsh H S T D to Wolverton Centre Sidings on 20/09/2023. From Realtime Trains, an independent source of train running info for Great Britain.
www.realtimetrains.co.uk
However, I am not sure whether 5Q81 will still be 166201, which has been at Wolverton since 03/08, or 166202 which has been at Wolverton since 21/08 and would be due to return if the usual 4 weeks for the refresh was being followed?