The Gorse Fox is delighted. He's smashed it. He has completed the coding and testing and can (and indeed has) applied all of the tags/labels that have been used over the years in this blog to the private blog. This was no mean feat.
The Gorse Fox needed a program to extract the tags and the post ids of the posts labeled with each tag, then another to import the tags into the WordPress blog and then update the relationships for all of the posts (and the counts for each tag). Lots of code and lost SQL... but done.