Thank you to Taupiro.
I actually ended up using a similar script to yours before I saw your reply.
My script is as below:
XMLREQBODY,substr(xmlreqbody,(Instr(xmlreqbody,'PersonNumber')+13),(Instr(xmlreqbody,'/PersonNumber'))-(Instr(xmlreqbody,'PersonNumber')+14)) as PersonNumber
(This is...