Apply the xmp to a photo using PM, and import that photo into Lightroom. Then in the Metadata panel, save the photo's metadata as a new Metadata Preset.
thanks for that John thats actually how we are doing it but apparently you can do it by importing the xmp file straight into lightroom? I'll give adobe a ring on monday and see if they know anything
It isn't possible to import a .xmp metadata file directly into LR, though you can do it in Photoshop using FIle > File Info > Import. As John Beardsworth indicated, you have to apply the .xmp to a photo using PM or PS, then import that photo into LR (and make a Metadata preset if you want).