Thanks for the responses guys, very useful, I really appreciate it!

Nick, (as far as I understand, anyone can correct me if not) the evoked potentials test records how long it takes for a stimulation to be recorded as an electrical response in the brain. So in the one I did I stared at a screen which showed a red and white checkerboard pattern ,with the squares alternating colours), with a black dot in the middle that I had to stare at. There was electrodes on the back of my head and they recorded when the signals reached my brain I guess. For someone of my age doing my university degree they said it should only have taken 90ms but for me it was 120ms.

To Mark, yes the neurologist said it wasn't an overly common test to do. But yes any delay would hint at a problem. I've not had any other tests done either. And now that I am back in the UK they don't do the evoked potentials test at all...or anything it seems?! haha.