Hi Matthias,
short answer is yes, but with a big caveat. What we can do with relative ease is the following:
Create a new placeholder branch in your codeset, something like "Recovered codes", and place in there the recovered branches, with new "parent codes" called something like "recovered parent 1", "recovered parent 2" and so forth. Beneath each recovered parent all the child-codes that went missing will reappear, together with coding data that is currently missing.
The problem is that we don't have a quick way of finding out the name of the original parent codes, so we will need to use arbitrary names for the recovered ones (like "recovered parent N"), this in turn means that you will have to inspect the coding applied to the child codes in order to figure out what each recovered branch stood for.
If this is acceptable, please let us know, we should be able to proceed as above during the current working day - I will then send instructions on how to proceed (assuming you'll be able to reconstruct the original name of each recovered branch).
Alternatively, if you don't feel the above will allow to effectively re-join all the dots, we can use our backups to recreate an off-line copy of the database as it was before the deletion, find out the names of the deleted branches and restore all data accordingly. Unfortunately, this requires much more work (and a lot of care) so it would incur in a significant expense: we would need to charge you £500 (+VAT, if applicable) for the privilege. If you wish to follow this latter route, I will need to know as precisely as possible when the deletions happened, so to capture the state of the database at the correct time (if possible). Also, I cannot guarantee that our backups currently contain the correct data, it (mostly) depends on when the deletions happened, so I would need you to please tell us the date as soon as possible: we don't keep backups forever, so the sooner I'll know the deletion date, the more likely it will be that we still have a copy of the correct data in our backup sets.
I hope the above is clear, please do let us know how you wish to proceed.
Sergio