Firstly, please use another person to do tests like that,
As that is a dangerous way to do self-testing,
Handbrakes are not too hard to fix on VY's,
The Ecotec engines are usually very reliable with minimum of faults, apart from the usual general service items that needs to be done as they age.
I am assuming it drives and stops ok,
Depending on its age, could mean general wear and tear
How many K's?
What Year?
Has it got service history?
Has it been serviced?
Has the Auto been Serviced?
Without hearing it, could be a simple fault,
General lifter noise,
Low oil
Wrong oil
Faulty lifter,
Worn Cam,
Exhaust leak,
Vac leak,
Drive belts
Either of the 3 pulley/s [assuming its not a L67]
Water pump
Alternator
Power Steering Pump.
To test to see if its the last 4 items,
Remove the drive belt [take photo of how its installed first]
Start the Car and run it 30sec's and see if the noise is still there.