Read XMP subpacket?

Is there such a thing? I have an XMP array that I can iterate over and get the 'top level' value strings I want no problem… Here is my issue when the element I want is a 'subpacket' I can't find any methods to access this? Is this straight forward and I've overlooked something obvious to those versed in XMP (Im a noob at this as you will see… Eg:

<xmpMM:Manifest>   <rdf:Seq>     <rdf:li rdf:parseType="Resource">       <stMfs:linkForm>EmbedByReference</stMfs:linkForm>       <stMfs:reference rdf:parseType="Resource">         <stRef:filePath>/Users/marklarsen/Desktop/Gent Mag/image001.tif</stRef:filePath>       </stMfs:reference>     </rdf:li>   </rdf:Seq> </xmpMM:Manifest>

'Manifest' is actually a much longer array but… What I have no issue with is getting property 'stMfs:linkForm' where Im falling over is how do you get 'stRef:filePath' xmp.get.property() does not appear to work? I've tried numerous ways now with no luck so I need to ask… Can't afford to beat any more kit to death or throw keyboard down the garden… TVM