Tim S wrote:
So my next question involves your definition of what constitutes an in-house movement? One that is entirely produced in-house (including the hairspring etc) such as Rolex and JLC, or one that is mostly (say 75% or more) in-house but maybe say acquires a hairspring from a 3rd party vendor...
I'm being pedantic I know but I thought I'd get to the nuts and bolts of the discussion

I would say designed
and built by the company. That doesn't mean that all the parts have to also be made in house, but a lot undoubtedly will by virtue of the fact that the movement is a new design to what's already out there. Therefore -
- The B01 is a true in-house as it was designed and built by Breitling in Breitling's factory. That is enough for it to be an in-house. At the far end of the scale you have Roger Dubuis (and Seiko, as mentioned) where
everything is made in-house. That's obviously the purest form, but IMO design and built is enough for a movement to be an in-house.
- If a company hasn't designed the movement then it can't be called an in house even if they make the parts and assemble them themselves. The Breitling B13 is an example of this as Breitling apparently machine the parts to make the base 7750, but the design isn't theirs.
- If a third party designs and builds a movement for another watch manufacturer (and only that watch manufacturer) then the movement is a "brand exclusive" but not in-house. The Omega 3313 is an example as Frederique Piguet make it for Omega, but only for Omega. (OK so Omega had input into the design of that movement too but that just muddies the water even more!

)
- If a company designs a movement but gets a third party to build it, then that's more trickey to categorise! I would certainly argue it's not a true in-house, but it's more than a brand exclusive. Difficult!

The movement in Roff's Louis Moinet falls into this camp.
Ultimately all of this is semantics and opinion, but this is what I go by.
Add the Tag calibre 1887. Claimed to be in-house, but based on a design that was licensed to them by Seiko. For all intents and purposed, I think i still consider it to be in-house. Maybe in-house with an asterisk?