But, upon further investigation (Wiki) I found that it did actually come with Adobe CS3. With all the machines in college being re-imaged. Adobe CS 5 and the whole of Windows had probably been installed from scratch and hence Arno Pro would have been lost.
Thankfully I found the Adobe CS3 premium disk and found the fonts dmg file:
Adobe\ CS3\ Design\ Premium/Adobe\ CS3\ Design\ Premium/payloads/AdobeFontsAll/AdobeFontsAll.dmg
and within found the Arno Pro font family. odt. Sorted!