As for 'Integrity's' comments... "it's also quite a mission to convert over to the LSE as i spent the last two days going through the process"...
That is untrue.
1) Go to www-au.computershare.com/Investor/#Home?gcc=au (no login required)
2) Click on 'Company Info'
3) Type in PM8
4) Scroll down and under 'Company forms', next to 'CDI Cancellation - AU to UK', Click on 'VIEW FORM'
5) Print out the 1 page form and read the signing requirements. After you've spent the 3 minutes filling out this tiny form, post it to: Computershare Clearing Pty LtdPO Box 103 AbbotsfordVictoria 3067 Australia