Progress!
We now have a mid June ticket to Zurich and an early/mid July ticket home from London.
My wife has some Swiss Francs which are old & can be cashed-in despite being expired but only at a specific bank in Zurich, and hadn’t happened to be going anywhere via Zurich for work prior to giving her employer the bird. It’s a reasonable amount, so since we were going to Europe anyway may as well have a look at Zurich, plus we’ve been wanting to go to Lausanne for a while.
Then we need to be in Brussels for the night of 2nd July and London the 4th.
So I reckon I’ve got about a week to organise between Lausanne & Brussels; I’m thinking probably 2 or 3 cities and train in between, I don’t think it’s worth the hassle of finding parking to rent a car (plus I’m not very good at just finding stuff to do unplanned while driving through places & from experience the French road system doesn’t encourage confused foreigners to get anywhere off the autoroutes).