Ok, I take it that no one has done this before?
Being non technical, I am not comfortable with playing around with databases.
After starting this this process, I had to change it a little to work properly - so this is what i did:
1. install the first WP blog on the new server and set up the hive, as per the installation instructions on this site.
2. copy accross from the WP sites on the old server the themes and plugins for all the sites I want to put into the hive on the new server.
3. Do a WP export (under Tools in the dashboard) from all the old blogs on the old server.
4. Change nameservers of amy domain names you want to continue to use to point to the new server.
5. Set up the the 2nd, 3rd...etc sites on the hive by creating a sub domain, or addon domain (to use your domain names) in cpanel in the new server, and pointing this to the root directory of the first Hive site. Type the name of this domain or sub domain to install WP in the Hive. You must activate the wp-hive plugin before setting up the next site on the hive.
6. Do a WP import in the new WP install (under Tools in dashboard)
7. Activate the same theme & plugins
8. I set up a seperate upload folder for each site in the hive (under settings, miscelleanous) in the dashboard) - you don't have to do this - for me it is easier to keep the upload files seperate.
9. Copy accross the contents of the uploads folder of the old blog to this new uploads folder (easier to do using an ftp program)and change any links to point to this new upload folder
10. You may have to reconfigure the site to get looking exactly the same as the old.
11. Repeat for each new site added to the new hive
It maybe a little long winded and there maybe a better more technical way to do this.