Re: Did they really steal it for hundreds of thousands?
It's worth a lot, because it's specifically details of someone who has had an accident in the last few days (if they've got to the point that a hire car is being delivered)
This is not random cold calling, "Oh hello I'm calling about the accident you've had". This enables the tossers buying the data to be a little more "Oh, hello Mr Jones. Just a followup call about your accident on the 3rd July, we've been instructed to conduct an interview as your car ABC123 was so badly damaged we need to check a few facts to get the compensation going". It's a little more believable.
Once they've got their foot in as "solicitors" (I'm sure they're called that legally, if not ethically) then there's a huge amount of cash to be had. Firstly, they'll tell the "client" to send their Enterprise car back, as they can arrange a better one (You don't have to accept the insurance's hire car offer, you can arrange it yourself and charge it to the third party's insurance). This will be for £200+ a day rather than the basic Enterprise rate. Naturally the solicitors are paying a nice cheap rate, but the value on paper to the third party is £huge.
Then they'll start claiming on your behalf for costs - loss of earnings, loss of "enjoyment of personal time" (i.e. you hurt your little finger so couldn't play golf), loss of contents of car, stress etc. All this gets charged to the third party by the solicitors, and you'll get it minus a cut..... OR it gets charged to you in the event it turns out you were to blame. They don't care, they don't ask questions, they send the bill anyway. You can try and deflect it to your own insurers but they'll likely tell you to jog on, since you didn't use their own legal protection and hire car.
Essentially, if you've had a crash, you're worth a LOT of money. 30 days to resolve a claim at £200 a day car hire plus a cut of personal injury? That's worth more than 50p for a phone number.