Hi Miles. Yes, the position over the Central London trike taxis looks as though it must come to a head sometime. It would be good for the users to be warned about the regulations, but I think the authorities are in a trap there. If they warn on what's being done but don't take action, they're condoning the breach, so they stay silent.
I found a similar situation locally. When a local authority wasn't looking after walker's interests due to lack of funds, I spent a year and a half voluntarily cutting through a network of new footpaths in local woods and building fences and gates etc. I should have asked permission, but couldn't for the following reasons. If the Council officially knew and approved, I'd have to have had Health and Safety training first. Trouble was, my age meant I fell outside the upper limit for expenditure on training, the need to look after local taxpayers interests etc. So they looked the other way, happy to get the work done, and I did it anyway regardless. The follow up is that they can't acknowledge the existence of the paths, despite many visitors and two Wildlife trusts coming from over a wide area to use them.
It's a mad world.