Thanks for the advice above both. So it doesn't need to be a friend who knows you well? It could only be someone from home if that's the case and it seems suspicious that they would give a reference for someone living in a different country. I guess I will work something out.
For the overseas checks, I already have the police checks for both places I've lived, but I was wondering as one of the countries is a nightmare if you're not in country. The UK and Irish ones should be no issue.