I notice this 39mm model is still shown on the AP Factory website, but with the words "availability to be confirmed". I believe it is no longer in production with the newer 41mm option.
Honestly Andy, I never think about it on my 15202, which as you know suffered the same issue. But mine was corrected so quickly, so professionally, and under warranty. I know it is different from your position. The shame is that you miss out on a great brand, and they miss out on a passionate collector. Maybe in time you can return...
I compared 'that' situation to a recent issue with my BMW. It's 7 years old, out of warranty, full service history but not all from BMW which had a timing chain issue..! It is potentially a known issue but after 5 days in the BMW garage and a bill of £2500 BMW then said they would pay all costs...!!! Now THAT is customer service and I will always buy BMW'S in the future and praise them to anybody who asks.
I think 39mm is the perfect size for a RO. It would be a mistake from AP to not offer to its customers the possibility to choose between both sizes IMHO
If I did not have a 39mm, no way would I pass at owning a 41mm. And that one does offer a unique movement feature with the double balance wheel. So while I prefer the 39, for an Openworked model you can do either.