The newer one is supposed to be 150 mm longer but it all depends where they have added the extra length.
The problem with a lot of boot space is not so much the capacity but the size and shape. My Leon estate had a very good boot space (620l) but the opening was almost pear shaped which restricted what would fit in and then most space was around and above the wheel arches making it useless.
Plus trying to get 4 people and a large dog in, is no fun.
So may be around the dealers again