VS 8

We're booked onto VS8 in December and the departure time is 19:15 rather than the usual 17:30. This appears only for Mondays and Tuesdays.

Interestingly VS 7 does not change it's schedule so it's not to accommodate a later arriving aircraft.

Is there a reason for this and is this correct?

Just thought it was strange and because we're making plans for arrival wanted to make sure it wasn't some kind of error.

It might be if the VS24 is cancelled due to light loads they have combined the flights and set the time at a half way house.