Thank you Hobbit and Lilpronaz,
That was excellent information and the letter from IWC is a revelation.
I did send it in to Richmond last year for an evaluation and accuracy check. The comment was "no service required, running as per specs".
With the information & rationale provided by both of you, Richmond's service staff's comments above could have actually meant "don't bother us, we're too busy or bring it back when it's broke"
May try Singapore then and ask for the crown back as suggested!
Thanks Gentlemen. Appreciate it.