This is my thinking regarding the keys too. These things perhaps weren’t immediately considered very important, and over time assumptions and suppositions became hardened and entrenched.
On who knew about the pub, AS says Suzy was ‘preoccupied’ with finding her belongings. But did he deduce this based on statements made by her colleagues, or simply from her behaviour, eg the calls and plans she made to retrieve said belongings across the morning? It’s not clear to me.
In the 80s would your bank also have known where you worked and how to reach you there? I didn’t get a bank account until the 90s, I don’t think any of the banks I’ve used since then have ever had my employer’s contact details as well as my own. I wonder what the exact sequence of events was that morning? Did Suzy call her bank (perhaps leaving with them her work number in case they needed to reach her?), then the pub called the bank, then the bank called Suzy back using the number given? Or would the bank have had that number anyway, a sort of ‘in case of emergencies’ type of thing?