Unsure if this has been posted yet, but this is a quote from the Cally Sleeper website:
I'm guessing this is due to the consistent late arrival of the Lowlander stock. Link below:
https://www.sleeper.scot/service-alterations/
Boarding Time Change – 3rd June 2019 onward:
Northbound Lowlander – London Euston to Glasgow / Edinburgh: From 3rd June 2019, boarding for these services has been changed to 22:30
Boarding times at all other locations remain unchanged.
I'm guessing this is due to the consistent late arrival of the Lowlander stock. Link below:
https://www.sleeper.scot/service-alterations/