Regarding the EZY GVA route from SOU, what strikes me is the incredible 426% increase in pax numbers on that route from December 2016 to 2017. I think this just shows the potential available from SOU that an airline such as EZY can unlock with the right routes, fares and marketing.
What's also interesting is that Flybe don't appear to be suffering from the competition, in actual fact they've doubled their numbers on the route since the year before too. Having another carrier on the route increases visibility and footfall, and Flybe may be benefiting from EZY passengers who go one way with one carrier and return with the other, for example.
No matter what the finer details are, it's great to see such a large increase in numbers on that route and hopefully provides food for thought to EZY for the future.
As another example of competition at SOU increasing a market for both carriers, look at the growth in numbers to/from AMS over the last couple of years.