Thanks for all the help guys, I had my audition about an hour ago and I honestly felt it went rather well. I know that I was better than a lot of the people there, and I think I was one of if not the most confident while doing it (despite not having sung solo infront of anyone since I was 5). I think I have a good chance of getting a non-chorus part, so I'm pretty pleased with that anyway, even if I don't get Enjolras. All these tips were very helpful, thank you! If anyone is genuinely interested in how I do, as I won't find out for a few weeks then drop me a message and I'll tell you.
Thanks again!