Foreign and English original language swapped

In order to make interface text user friendlier we created a Custom Language labeled as en-intra. Strings that were too complicated or too much Drupal jargon were rephrased in en-intra and it was set as the default language and the original en was disabled. Now the users see our interface language and if there are questions related to explanation text, we can adapt just any interface text to our needs. We thought this was indeed a cool thing in Drupal, but......

I cannot tell with what upgrade (of core supposedly) it was, but something went wrong. When do a search, our custom text appears as the original language and the default Drupal English has disappeared. At some point "en" got overwritten by "en-intra". In some update somebody must have forgotten that the original language is not always activated, nor the default.

I am wondering now how to fix this? I would not like to loose our customisation work but it is now totally mixed up with the Original Text. When I do a search on a string that I know only appears in the custom text, then it turns up in the original text and all appear as untranslated!

I'm thinking of:

• exporting the en-intra, which will contain the original language strings mixed up with my modifications.
• restore the original text
• delete en-intra
• creating en-intra
• exporting en-intra
• usding diff to compare the two exports to recover my tranlations
• creating manually a .po file with my translations
• importing the resulting .po file in en-intra

The question is how to restore the original text? Anybody knows a better solution as my suggested procedure?