When you move your hand around it, does the volt increase or decrease?

It decreases. Same thing with loud noise and general movement around the room.

Also you need to isolate it. Wrap each tube a bunch with paper. Or something. Not really sure what would be the best option but the idea is isolation.

Okay, this is interesting. Nice idea to stop the interference.

My final set-up will however be buried in the garden so I don't feel like this aspect is too important. I imagine it will give a steady output once it is in the earth. But let's see...

He became very interested too. He also said, as is, its the same capacity as a mini solar panel.

Unfortunately it turns out I was reading my multimeter wrong! Am still new to this. In fact, what I have here is 1milliamp so will need to add more cells in parallel to increase amperage.

That being said, I believe the total power output will go up once I get it into the ground where it is supposed to be. I would in fact be doing all these experiments outside if it wasn't so cold.

Many thanks for your help!

And to your friend too :)