Ironically, I just went out for one last go, it had been raining a little bit after being dry all day, and it came straight off in my hand, pretty much. So the best way to get your wipers off your car is in the rain, apparently...explains why my Mk4 Golf ones packed in in a downpour, they were probably trying to jump off the car!
So Fabia wiper now fitted, Valeo retrofit-aero front wiper blades fitted, I should be 100% more stylish now, and about 1000% more visibility in the rain! Just need to keep an eye on the rear wiper, make sure I've done the nut back up tight enough, I assume it's supposed to be on pretty tight as there was a fair bit of resistance when I took it off this morning to try and get the old wiper arm off?