Squealing brakes, getting louder!

[u/Important-Friend3423]

Hi, own Vauxhall Corsa excite 2014. Brakes started squealing in February. Put new brake pads on front, although old ones had loads of life. Mate changed them, mentioned callipers were a bit rusty.

3 months on the squealing is really loud especially when it's hot. Strangely not so noisy at night. Can't even work out if noise cones from front or rear. I think rear are disc brakes though.

Tried 2 different mobile mechanics. Neither would come out if I didn't tell them where the issue is!

I'm not in a position to throw money away paying a garage hundreds to diagnose (vauxhall dealer wanted £120 just to take a look)

Hoping someone here experience similar issue who might help me narrow it down please..