Go to your ACP on live board - System - Backup Database - Either make a download file or store local.
If you store local (easy option) open up your FTP client , browse to your root of phpbb and find /store . Your file is there. Right click and Download to your desktop.
If you downloaded the file from ACP then ignore that. Open empty board. ACP - System - Restore Database and select the database file on your desktop.
If your database is big then the acp backup will not work as good. It is best to export it via phpmyadmin then go to the new database using phpmyadmin still and import it there.
Make a copy of the forum files and use them files as they will have all the mod code in them and then when you connect it to the new copy of the database, that will have all the mod date in it.
@Fowlers post.
Actually it depends if the host changed some PHP settings to allow files larger then 2 MB's, If it just doesn't work with phpmyadmin then use bigdump
I know this is a big ask, but is there anyone out there willing to do this for me.
I've spent hours developing my test board only to be told that I need to transfer the database or start with a vanilla install, which would mean losing a years work on the live board, and probably losing what few members I do have in the process.