Good Evening,
I work for one of the companies that is currently looking at the UK ventilator challenge, I'm a mechanical engineer to trade, but have not had previous experience with ventilators, so the past couple of days has been a crash course in terminology and history of ventilator design!
My own thinking at the moment is that a ventilator design that is relatively proven, but from the era before PLC/microcontrollers might be the best bet for restarting volume manufacture - something that's simpler, proven in service, but not over-engineered and while having fewer features, is less likely to go wrong.
I've been looking for information on the following models which seems like the right sort of era - but happy to take some guidance on this:

British Oxygen Company (BOC) models:
- Harlow
- Beaver II
- Cylclator

Manley-Blease
- MP2
- MP3
- Pulmovent
- Servovent

W Watson & Sons
- Barnet Mark III Ventilator

There is currently a programme of work underway at the moment (as I understand) to discuss the availability of designs from current manufactures, but I think that something dipping back into the archives might be more realistically manufacturable with the supply chain that we have in the UK/components that might be held in stock here.
Any feedback and pointers towards available resources (service manuals, BOMs/parts lists, drawings, photos) would be much appreciated
Thanks
Murdoch