Okay, just to update this, it went back to Blancpain in the end. Returned yesterday, all done, repair/service completed, both barrels renewed, a new sapphire, and a minimal resto of the case and bracelet performed. Looks fab, appears to be working as it should now, and was turned around pretty swiftly I thought with good communication.
Wasn’t cheap but not stupid either; no qualms about recommending.
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