OK, a) i work in a hospital, b) the missus is a nurse. I have been thinking about exploring this avenue for a long time but it's fucking difficult.
Drugs like MS Contin, Pethidine, Ketalar, etc are kept in the dangerous drugs cabinets of hospital wards and hospital pharmacies. Getting into one of them is damn near impossible, and if you do getting the drugs without anyone noticing is impossible because everything is logged by 2 RNs (registered nurses). Pharmacy is even harder.
As for take-home - you can get take home morphine, pethidine etc, BUT for the opiates to be take-home you must be in SEVERE PAIN! Not panadeine forte pain - chronic cancer pain.
If there was an easy way to get your hands on these babies, i'd probably have given it a go. Funnily enough, i've heard that sourcing morphine and similar opiates is sometimes possible through certain "illegal-drug" peddlers...
Good luck bro, but with all the shit that went down in the US regarding oxycontin, i don't think you'd be able to have much chance getting it here. Or you could work on your chronic debilitating pain routine...?