I cleaned my hood with a cleaner from Gtechniq and the foam turned green so I knew it was removing the algae, unfortunately, the froth hid the damage I was doing to the stitching on both the hood and the window surround so be gentle or at least targeted; restitching through the thick material is a long and painful job!
I have the same wear on my hood, interestingly, I bought a second hood because I wanted the glass rear window, on the hinge that you mentioned it had an additional plastic part that I assume MGR added because they were aware of this problem. When I did some searching I found that Mike Satur was selling a similar aluminium part.
Mine did exactly the same although it's not a VVC, I replaced the gauge sender but it made no difference, eventually I traced it to the thermostat, I guess it was opening up suddenly on heavy acceleration and flooding the sensor with cold water. I took the opportunity to do a PRT conversation at the same time.