How can I undo a catalogue import?

Hi, I just did something that turned out to be unexpectedly bad!

I went through the process of exporting some pics to a new small catalogue, did some minor work in the new catalogue and then re-imported the small catalogue back into my main catalogue.

I expected this to import the changes, which it did. BUT it has also created virtual copies of every single pic I exported to the small catalogue - about 3300 of them. Naturally I now cannot remember exactly what import options I selected.

The import is showing in the 'Previous Import'. Each one has a 2 indicating there are 2 versions of each. But if I select and try to remove, it looks like it wants to remove both versions.

If I go into the original folders, each pic shows with the original and the virual copy next to it. I can filter on the virtual copies and so could select them all and remove them that way.

But I cannot reacal if I had previously made any virtual copies, which would also get removed.

Anyone got any ideas how to solve this problem?