That first Gumtree link is absolutely insane. It looks like a full time job for multiple people.
> At least for a short while, and I do not understand why, bicycle theft was somehow linked to terrorism by London's police.
Counter-Terrorism Patrol Unit.
IME speculation: for security-adjacent personnel, recovery efforts (equipment, fraud, etc.) are a great way to quantify the work you do when you don't otherwise generate revenue. You can't take credit for disrupting events that didn't happen [because you intervened], but nobody can argue with you recovering or clawing back $x in lost/stolen assets.
They were probably tasked with patrolling for misplaced explosives and other drama, but since incident count is low, they were given supplementary tasks (like tagging bikes they come across on patrol) to justify their salary and foster positive PR.
I had a bicycle stolen, and after filing the report the police phoned me to ask for more details on the lock I'd used.
I later found it on Gumtree, with a description ending something like "Call Peter on 07123456789, meet at Forest Heath Station". Putting the mobile phone number into Gumtree's search brought up about 50 bicycles, "Call John" "Call Dave" etc. I emailed this to the police, and had another phone call thanking me for my incredible investigation skill.
They said they would go to find Peter/John/Dave, but would only contact me again if they found my bike, which they did not.
I'm very suspicious of accounts like [2] "Mr T" with "Cash only" and a huge selection of bicycles.
[1] https://www.bikeregister.com/news/putting-a-value-on-protect...
[2] https://www.gumtree.com/profile/accounts/48e9b2ff00d3f04e27f... or similarly https://www.gumtree.com/profile/accounts/b8b756750f2960d115b...