Vauxhall astra mk4 elec motor like whining noise?

[geordie_08]

astra 1.4 ls petrol estate manual
noise sounds like a electric motor or something only begins to happen after a couple of hours of driving mainly heard when accelerating/decelerating in low gears

i will give a brief description of whats been happening last 12 months with the vehicle
had broken engine coolant pipe which was leakin has been repaired
had radiator+fan replaced
had clutch replaced
knn airfilter installed
the car apperently seemed very hot to a mechanic
also ecotech platic cover rubber fasteners broke leaving oil cap loose which made oil cap come loose on occasion allowing oil to spray out
temporary measure in place to stop this happening

I have recently had faulty battery trouble so i had resorted to bump starting but now has replaced with second hand battery which seems ok

any help would be grately appreciated as i dont want to have to fork out a fortune if something bad really happens this car is used to make me a living delivering pizza and transport my children to school daily
cant really afford anything real expensive so scrapheap challenge here we come!!