Complex sentence: A small British Indian force made up of detachments from several different units (including the Duke of Wellington's Regiment) defended the bridge, but 16th Brigade and 46th Brigade of the 17th Division were still further to the east, cut off.
Split into simpler sentences: A small British Indian force made up of detachments from several different units defended the bridge. Much of the 17th Division was still further to the east, cut off.