Update today. I had a call from Mark Blowers this morning. The 5176A is off to an independent level 3 trained Patek guy for inspection where it should get priority treatment. Hopefully it should be a simple fix, and so the watch should be soon back with me, after a full wrt and test with no quibble full money back in 12 months if any further issue. Should be a bit more off the price too.
So turn around should be much quicker than off to Patek Service Centre. It may even be back in my grubby hands in one or two weeks.
Nb: I see a dark green rubber version for sale so I assume you can still order those? Have you checked your AD?
Martyn