The current SX plan is as follows;
As from 11/03/19 - Diagrams 8, 9 & 10
As from 08/04/19 - Diagrams 2, 5 & 7
As from 29/04/19 - Diagram 4
As from 20/05/19 - Diagrams 1, 3 & 6
Diagram 6 could go earlier than 20/05/19, if required.
SO and SuO diagrams should cease from the weekend before so the last day of normal service on GWR should be on Friday 17th May.
The picking of diagrams 1 and 3 (both lunchtime Pullman workings) as the last pair was far from co-incidental and the last ordinary SX departure from Paddington should be the 21.03 on the 17th, nicely timed for a slot on the 22.00 TV news.