I just wish I could permanently disable this annoying, useless feature
It's not useless - it will save you a small amount of fuel and slightly reduce the pollution you generate. I don't find it annoying - I barely notice it in normal driving. The engine has always restarted and is ready to go by the time I've moved my foot from the brake to the accelerator pedal. In what way is it annoying you?
im thinking of getting a mk3 and this is one of the features i hate along with tire presure sensors, auto lights/wipers, auto lock and walk away, push button start and no real radio dial just touch screen control
There are no tyre pressure sensors. The vehicle just compares wheel rotation speeds and warns of an anomaly. It's a simple and reliable system. Auto lights mostly work okay. Auto main-beam is nearly perfect and a huge boon. I agree on the infotainment unit though. Poorly designed UI, too much reliance on touch technology and buggy. Nothing says "congratulations on paying £18,000 for a new Jazz" quite like having to drive for two minutes listening to the engine and road noise because the infotainment system is struggling to boot up.