If the fan is the only thing giving problem with your power supply, i would recommend just replacing the fan. The psu you currently have a very good unit, and if not showing any signs of fatigue(besides fan) it should not be a problem. Also, the I3 and 1050ti are very efficient, your PC will only go 400w+ occasionally, so your current psu is taking less load.
If you are anyways going to persuade yourself to buy a new and expensive power supply (some of which i wouldnt pair with such a budget system), the Evga G3 550w is more reliable and better performing.
Thanks Trafalgar747, I was under the impression you couldn't open/replace PSU components?
Yes all seems fine other than the fan (if I stop the fan the noise stops)
Definitely open to other product suggestions if you have any that would suit better, not set on those - main thing is noise level/build/reliability.