Complex sentence: Some Canadian and British infantry divisions had been temporarily equipped with M7 Priest self-propelled guns for the D-Day landings, which had been replaced by towed Ordnance QF 25 pounders.
Split into simpler sentences: Some Canadian and British infantry divisions had been temporarily equipped with M7 Priest self-propelled guns for the D-Day landings. These had since been withdrawn and replaced by towed Ordnance QF 25 pounders.