Document when it stops, winding behaviour, recent impacts and the positions in which it happens. Be honest about the watch and request an assessment before approving work or ordering parts.
Clarification for “Service enquiry: information a watchmaker can use”: the point beginning “Document when it stops, winding behaviour, recent impacts and…” belongs to the question as written. It should not be read as a report that a new check, purchase or experiment has been completed. Review focus: scope. Keep the stated question separate from any broader claim.