Hello from Sologic Solutions,
We are Kolkata, India based Software Development Firm catering our clients with PHP, Wordpress, Codeigniter, Laravel, CakePHP and Membership Sites development.
We have reviewed your Job and understood your requirement. We can write a standalone php script protected with login/pass and can be called via external menu or put into cron, migrate data from one database to another, tracks previous migration and avoid duplicates.
Please message us and we can discuss the project in detail.
Kind Regards,
Sologic Solutions