your corsa gearstick has gone sloppy because it needs a new gear linkage. its a common problem on corsa'a and the part is about £60 from the vauxhall dealer

Had that many cars i can't really remember but you either have to push gearstick down then into reverse or pull gearstick knob up to engage reverse. Defo one or the other :)

its controlled by the button on the side of your gearstick (auto).

it is next to the gearstick. arnt i help full ayy? ;)

They are for increased power in lower gears and that can be switched on and off with those buttons.