Thanks for all the replies/advice/help. I never would have thought 3 identical bikes could be so different!
I popped along to the local dealer and they had the GasGas and 701 side by side. The GasGas was notably taller and I struggled to get both feet on the ground whereas I could on the 701. It's hard to explain but they felt very different, I definitely preferred the 701 to the GasGas. To me, it felt a lot more refined and it was the one I kept looking at and sitting on. Which said it all really.
The 701 in the shop was their ex-demo with 105 miles on the clock. They offered me such a good deal on it I couldn't say no. I collect it next week!