Double note duration doesn’t seem to tackle this:
A is original, B is doubled notes
As long as you have Insert mode turned on you should find that the note values themselves are correctly doubled, like so:
Note though that the tuplets, which are separate to the notes, are not doubled.
In these sorts of passages it’s probably safest to:
- Copy and paste the passage.
- Turn on Insert mode.
- Filter and delete the tuplets.
- Apply Double Note Values.
- Add tuplets to the whole passage.
This is much quicker to do than to explain.
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Thanks! It took me a while to do it correct.
But, yes, that works 
Needs to be done per track stave though,
with extra care for pauses, slurs and dynamics.