With no disrespect for OP's had work, which I commend (and I must say I was particularly impressed by your stance on the NDA, which I thoroughly support), this was (to the best of our knowledge) one case. They could have made it a lot harder, but clearly weren't bothered.
I am almost certain that a litany of FSD law suits in the UK would be the sort of press that would make Tesla Corporate pay attention and then I suspect the gloves would be off.
I'd look at it like this
- Telsa overpromised (in writing) and failed to deliver.
- 2016-2020 were more difficult times for Tesla, the money-for-promise helped them demonstrate to the markets that sales were scaling, unit prices were high because of addons, and everything is rosy, please invest!
- Tesla are now well capitalised, and frankly refunding every buyer of those early cars wouldn't make much of a financial impact. Early model 3's (before the website watered down the claims to a point they might stand a chance of being defensible) are few in number, FSD purchases fewer again...
- Legal know that the marketing claims would be extremely hard to defend in court, it's not worth their time or money to try
Hence, put up some barriers - You've got to gather evidence and raise the paperwork for a small claims court motion (Tesla including £500 of costs in the settlement is probably "worth it" for the barriers created)
Then, OK, we'll give you back the "loan" you gave Tesla, please sign this settlement agreement with NDA
What? The guy is willing to decline the settlement and go to court rather than sign the NDA? May as well provide a settlement without an NDA then - we'll lose in court and we can't impose an NDA on a court loss...
As ever, it's an iterative process to get things legally water-tight. The early days of Tesla were very smoke and mirrors to get things off the ground, some later legal settlements are a small price to pay for the results they've seen.