I need to make a locator for UK addresses and I know Open Street Map has very good data for the UK, I was wondering how I can convert the data for house addresses, which is in xml form, into a locator in Arcmap.
I think you're trying to create is working with Geocoding in ArcGIS.
Here is a video tha you can follow the instructions to do the geocoding in ArcGIS.
But before that you need to parse your XML data to get just the address. You can do it using a simple code using Python (it's installed by default when you install ArcGIS).
Is that make sense for you?