Hey guys,

Quick question. My mum's idea has got a problem it will only on speed 4

123 it won't work. Any ideas?

I think this might be your mum's problem, the heater control module.
https://www.fiatforum.com/grande-punto/267394-heater-blower-problem.html

Mine doesn't work either. I hit a curb once and it started working temporarily,

Heater resistor has packed up. Available cheaply enough on ebay - can be a bit of a pig to change though (usually in an awkward location)