Vauxhall Astra squealing coming from drivers side when car is warm on traveling on road not on tickover

assume it is not from engine but you could check drive belt is ok and not slack also belt tensioner pulley but as it does only when being driven i would check brake pads for wear and sticking caliper (brake binding)some pads have a wear indicator and when pads wear to a set limit it contacts disc and squeals to worn driver pads need attension also you could check rear brakes for binding