Complex sentence: Aside from the necessary adjustments to the design to incorporate local engineering standards and available components, the Canadian Valentines used a GMC engine, which being an improvement over the original engine was applied to British production.
Split into simpler sentences: Aside from the necessary adjustments to the design to incorporate local engineering standards and available components, the Canadian Valentines used a GMC engine. This engine, being an improvement over the original, was later applied to British production.