After I'd peeled myself off the ceiling given the untimely coincidence, I checked and yep, I was locked out of my account. Fortunately eBay has resetting your password well automated, so I was able to reset it and log back in again, just in time to see the item I wanted go for a third more than I was prepared to pay - I'm not too upset at losing it, there was a bunch of stuff I already have in the package, and the item I actually wanted, a set of out-of-print wargames rules, will eventually get an ebook version, so I'd restricted my bid to what that will go for when eventually realeased.
I still haven't forgiven eBay for the wheelchair fiasco, but praise where praise is due, they got it right here.
OTOH I may just leave Paypal disconnected for a while (and I'll be paying close attention to my next Paypal statement).
* Definitely not a false-positive misidentification of me, I hadn't done anything yet.