I've brought across about 3000 items from the old website. They seem to have come across intact. I know that not all of the items have come across. This may be, in part, due to the fact that some items are no longer up on the websites which originally provided them.
I have encountered a few bugs in the latest version of Joomla K2. Not all of the items seem to be appearing in the category to which they have been assigned. I am confident that they are there nonetheless.
In the spirit of the data's integrity I have migrated the creation date and the number of hits received by each articles.
There is a long road ahead of re-visiting all of these older content items, checking them and approving them for publication. I am close to the point where I can replace the old website.