A couple of things to consider, these cars don't tend to have much in the way of sound insulation on the underbonnet or firewall/bulkhead, and now no big air filter covering the engine like the earlier BBY/BBZ etc engines, or a cast aluminium sump - also these engines do tend to be a bit rough/noisy which might be the price you pay for having a reliable engine!
For what it might be worth, I drive daughter's 59 plate
Ibiza SC 1.4 85PS with 35+K miles quite a lot and it is rough/noisy when compared with driving my wife's 52 plate Polo SE 1.4 75PS with 104+K miles under its belt, but as the
Ibiza is a lot lighter and the newer engine 10PS more powerful, it flies when compared with the 52 plate Polo SE.