Complex sentence: Devine was sent to Essexvale to engage the rest of ZIPRA's armoured battle group, which surrendered when he arrived; the T-34 tanks were later found by the Zimbabwe National Army to be nonfunctional.
Split into simpler sentences: Devine was sent to Essexvale to engage the rest of ZIPRA's armoured battle group, which surrendered when he arrived. On inspection by the Zimbabwe National Army, the T-34 tanks were found to be nonfunctional.