For our 1.4 16V engine in the Ibiza (although it was the previous engine code AUA), the recommended intervals were: initial inspection at 90,000 km, then every 30,000 km, and replacement at 180,000 km or 7 years. However, as I mentioned earlier, I also believe that 90,000 km is a reasonable interval for replacement, considering that the 16V engine has 2 camshafts and 16 valves.
Make sure that both belts and both belt tensioners are replaced, meaning a complete kit should be installed.
Unfortunately, I've experienced this twice already: the timing belt (connecting the crankshaft to the camshaft) was replaced, but the smaller connecting belt (connecting camshaft 1 to camshaft 2) and its plastic tensioner, as mentioned before, were not replaced.
The water pump is also driven by the timing belt, so you should replace it at the same time.