I have noticed that several times in the last 2 weeks VS015 has been quite late departing Gatwick, is there a reason or is it just a coincidence?
Not sure what you mean by 'quite' late
According to the 'schedules' tool in the toolbox since the 1st August she has departed within 15 mins of its schedculed departure 9 times (one of those was even early!) out of 12
It has taken off very late twice.
This could be for a number of reasons - not all within VS control such as
Late inbound arrival due to late departure for numerous reasons including weather
ATC issues
Airport congestion
Mechanical problem
Need to offload pax who did not arrive at the gate and their luggage needed to be found.