90 without a doubt. You'll spend every minute behind the wheel regretting it if you go for the 70. It's the difference between easily keeping up with traffic or spending your days being intimidated by lorries.
Try both transmissions. The clutch on the manual is a bit sharp, and while you'll get used to it the auto is nicer, although that itself requires a bit of practice to get used to it (treat the accelerator almost like a manual and lift off the pedal a bit just as you sense the car is changing, gives a much smooth change on the auto.)
Pre April 2017 gives free or cheap tax as well, post is the blanket £165 wallet emptier.