Thank you very much for all your help.
I thought I'd let you all know which way we went. We decided to use Hibernate in the end, this took some convincing of the rather large DB team (Now a lot smaller due to our choice...).
After 3 months of working with Hibernate, we are happy that it can do all we need. The on-paper features that Toplink boasts over Hibernate (eg. multi-table one file mapping) are promised for hibernate 3.
I am now of the opinion that Toplink will become yet another sales driven technology (like Oracle?
) as Hibernate really does seem to have the ORM problem all sewn up.
A couple of other tips: The hibernate PDF docs are worth printing out. We bought a few books and all except Hibernate in Action just repeated what was already contained in the docs.
Thanks to all!