It would appear, during this period, that the down Sleeper is terminating at Plymouth around 0515, with a bus (or coach) from there at 0530 for Redruth and beyond and a train calling at usual Sleeper stops to Truro at 0550.
The up Sleeper will start from Truro at 2255, with a bus departing Penzance at 2125 calling at usual Sleeper stops to connect into it at Truro.
I guess that servicing and preparing of the Sleeper sets will take place at Laira whilst access to Long Rock is unavailable.
All trains, in effect, as well as the Beds which would be starting at Truro. There are
ECS▸ from Par to Truro for starters.