As I wrote earlier, I've just made myself a brand new pair of goggles! Because it was ridiculously easy and cheap, I thought I'd share the process here, so that others may take inspiration from it! :)
Firstly, I equipped myself with two empty cans of Redbull, mainly because these are aproximately 5 cm in diameter, so if you find other cans of the same size, they will most likely do. Using a nail buff, I removed the colour from the can, before painting the bottom with a brassy colour. I used Citadel (GW) paints, which demands a few layers, but most hobby paints should work. I left them over night to be sure they had dried properly. Next, I cut the painted bottom of the can off, making sure it was approximately an inch high, and them moved on to cutting a hole in the bottom. I now had the frame of the goggles.
I dug out some old leather I had lying around and cut out what was to be the "cuffs", the nose bridge and the straps. I also found small buckle to use for the straps. Sewing the all together, I next fitted the frames into the cuffs and added the "lenses", basically two sircles cut out from a sheet of transparent acetate.
Using a sharp hobby scalpel, I cut four small slits along the ridge of the frame, and stuck a tiny vintage brass coloured paper brad, using it's "arms" to keep the lens in place. And that's it! Goggles done!