Haha that's wild that you mention Psion because I already have a bunch of images/writing regarding them. Palm as well, but Psion is a lot more niche at least in the USA. Do you know which models you had?
The Psion 3 used an OS called EPOC/16, and the 32bit version became Symbian OS.
I never had a PDA device, and I was really late to adopt even a cell phone.
My father had an iPhone years before I got mine.
A big thing for me early on was the iPod though. It was a big deal to carry around 40 gigs of music, and I couldn't live without that thing.

Flock may not operate in the UK, but I can bet there is a counterpart with similar technology. I know you guys have the CCTV system so there could be some differences involved there as well. Leonardo's ELSAG system I believe is based in Italy.
All of our police here have cars with laptops mounted in them, and with Flock when they come up and ask you "where you coming from, where you going?" they could theoretically already know the answers.
The company itself also operates in very secretive ways such as registering it's business locations as other companies.
There are town halls where they vote against adopting Flock, and the city just does it anyway. It's the first time I've seen people actually react to the surveillance-state.