From the Sleeper websiteIts not going into Kings Cross, its going into Euston via the ECML and it goes via Motherwell and Carstairs to Edinburgh.
Only judging by what is currently showing on RTT that XC are running buses at Motherwell & looks like there isn't anything Scottish towards Lanark via P1 or P2 it seems to suggest that there might be an engineering block somewhere in that areaSunday 21st April
Summary of changes: Northbound services will depart from London King's Cross. Southbound services will arrive at London King's Cross. There is no service tonight from Watford Junction, Crewe, Preston or Carlisle.
(I believe Euston is closed over Easter)