John - this is my personal view of the situation from ~1800 and it is not to be regarded as 'gospel'
The way I think of this is in terms of the distinction made, or better implied, between the output of frame makers, movement makers and escapement makers. It is all to easy to get drawn into trying to define too precisely the lines drawn between these so called 'makers' and their products. When I use the term frame, I mean the fundamental skeleton - the minimum that is present in the most unfinished of unfinished movements - for these movements I happy to see them called raw movements. Such full plate frames consist of the plates connected by pillars and the balance cock. For half or three-quarter frames additional cocks to support the escape and fourth wheel may be present. Often the potences are present, but not always. I suspect that these 'frames' are most raw/primitive items that resemble the finished product that were traded. They were probably produced, completed, in a number of workshop with a single or group of workers with all the necessary skills without moving off-site. To be clear this is not to say there was not an active trade in component parts.
Various 'production paths' could be taken by these frames subsequently. Some may have continued to be worked on in the original workshop by others with the necessary skills - these might have been described under the term movement makers. The production of others may have been managed by that workshop but the work done by out workers. Others movements may have been completed by using purchased components - the possibilities are too numerous to continue. In any case it is really no more than speculation based on inferences rather than fact. Just because there is a list of 40+ different tasks that have been identified and individuals documented with titles that correspond to these tasks, it does not mean that this number of individuals were engaged in the production of any individual item. My opinion is that the number of individuals engaged in the manufacture of a single watch dropped sharply as the C19th progressed.
It is possible to use the term Coventry frame for some frames that carry makers marks that have been positively identified, but these are found in relatively small numbers (compared to the Lancashire output) and mostly after ~1850. However, there is also a respected opinion that a significant portion of the verge frames made in the C19th, and possibly earlier, originated from Coventry. Finally, I personally feel that rather more Liverpool runners and windows were copied and made outside Lancashire (only ceased as an administrative county including Liverpool and Manchester in 1974) than Graham suggests, but in that respect I suspect I hold a minority view.
John
