I can perhaps understand to a degree, but your posts are really symptomatic of a need to have your confidence boosted, despite the advice on the law which you have received.
There is NO regulated process by which VCS could pursue the keeper*, this is purely a contract issue and as such the next prescribed step FOR THEM is to issue a Letter before Claim. However, because they can and because they know it works, this doesn't prevent them from taking whatever other steps they want, as long as they stay the right side of laws regarding coercion and threatening behaviour, and the letter you've received is a case in point.
File and ignore.
The letter you've got reminds me of what happened years ago in London when, certainly in my area, there appeared a spate of 'A' board signs advertising MASSIVE GOLF SALE'. Of course they weren't 'sales' and eventually Trading Standards got involved. So did the boards disappear? No. They simply changed the wording to MASSIVE GOLF SALE Ltd(with this being in much smaller font) and formed a company!
No one is going to stop them sending these letters because they know that they can work. They have staff who dream up ever more intimidating terms and phrases designed to scare the unwary. And if you bite at any letter by responding, this would simply incentivise them to send another.
Disengage and force them to engage with the prescribed process i.e. LBC.
*- earlier in this thread you referred to 'we' in the context of their original notice and the unknown recipient. Is the addressee on this notice and subsequent letters a person and you or perhaps a company. The vehicle's not on a lease or hired or similar, is it?
