FYI if this may help others.
So, after 4 weeks of thrice daily monitoring of the visa appointment site, we finally landed 2 slots. Direct emails to the consulate and phone calls didn't help us to secure slots any earlier.
Too late I'd realised I'd made small mistakes on our application forms. (wrong postcode, wrong nationality). Direct email to the consulate (again) gained us a confirmation that this wasn't a problem and the official who would host our interview would fix and reprint the forms on the day.
There is no parking at the consulate building, but plenty of on street 90 minute street parking options and parkinghaus options within an easy walk.
The security chap was rigid about sticking to the appointment schedule when letting people in - very efficient, but tough luck if you arrived too early with no where outside to shelter from the rain!
There's a photo booth within the consulate, exactly the same type as found in rail stations and shoppings centres across CH, and the same 15 franc cost.
Despite having seperate bookings for myself and my OH, the assessor was happy to see us at the same time. We'd arguably overprepared, arriving with folders full of every document imaginable within the vague guides given in advance by the consulate, and everything in triplicate for each of us.
In our instance, our assessor was only interested in:
viewing the originals of our passports (which were returned to us at the end of the session thus allowing us to continue travelling whilst the visa is processed!)
1 copy of each of our passports, including every page that had stamps/other visas showing (didn't want to know about the 2nd passport I still hold from my birth country)
letter from each of us confirming intent to not work whilst in France for duration of this visa (we'd had our letters notarised especially, but that didn't seem to be necessary)
2 x utility provider bills for our house in France
1 x copy of front page of sales document for our house in France
1 x copy of bank statements (and didn't want to see all of them, just enough to prove we had the minimum level of cash available to live on for a year)
1 copy of our combined private health insurance (after much investigation, we wound up buying a premium package with Regency who did NOT require us to fill out a medical questionaire in advance and issued the insurance certificate on the same day as purchasing the premium, whereas other companies, direct and through brokers, who claimed that pre existings wouldn't be a problem, wound up trying to slug us extra premium loadings at the 11th hour and had delays with their medical board reviews and certificates being sent by snail mail)
The assessor had zero interest in our rental property and investment income sources; our personal asset/liability statements; our work histories.
We were fingerprinted within the session, and apparently our visas will be ready in 10 days, at which time only 1 of us has to return to the consulate with both passports, when an official will stick in those visas.
Whole process on the day was very pleasant, and I was assured by the official that the small forest of paper I'd used in preparing so many copies of so many documents, will be useful when we get to apply in future for the carte sejour.