unfortuntely thats the way in which the brake are on the 1.4s. The brakes on my 1.4 are basically crap. I have thought about upgrading the discs and pads. But think ill just do the pads and try some green stuff brake pads, with normal discs because the upgraded ones are tooooo expensive.
Plenty of people on here seem to have upgraded ZX brakes using discs and calipers from Berlingos - try a search.
I would think that would work OK - in my experience the back of the ZX 1.4 locks up too readily under heavy braking.