just bought a gs450h myself and although the boot size was a question in the end its not that small I managed to get 2 large suitcases in it for the holidays
but buy the car cause without a doubt its the best car i've ever had the power is knockout and the comfort and gadgets put a smile on my face everytime in go to get in it
ill get a tape measure this afternoon and take photos with some everyday objects in it to give you a better idea of the size
Its basically somewhere between a fiesta and focus boot in size