I've certainly noticed the uptick in Bristol punctuality - the number of text delay warnings I get has gone down significantly.
Agree with that, and the improved performance seems to be continuing through January.
I keep a close eye on two Taunton - Cardiff services that I use most often for my journey home from work, and their arrival time in Newport because I make a connection there. Statistics for arrival within 5 minutes of scheduled time look like this:
July 2018 - 14/34 = 41%
Aug 2018 - 27/45 = 60%
Sep 2018 - 27/44 = 61%
Oct 2018 - 23/39 = 59%
Nov 2018 - 13/20 = 65%
Dec 2018 - 29/31 = 91%
Jan 2019 up to today - 25/26 = 96%
No short-forms this week either on these services - though that's not long enough to call it a sustained trend.
Adrian