Possible Scam First Plus Claims Ltd?

Hello,
The other day I received a cold call form First Plus Claims Ltd saying they had been pursuing a case in the County Court with LLoyds Black Horse Finance due to a Loan with PPI I had previously taken out. They said that this is because they approached Black Horse Finance who had denied liability, so they had taken their case to court - and now won. They said that the 'regress' I was due was about £4k (me generalising not them), but that in order to pay it to me, I had to pay their solicitors fee of £469. I have certainly had loans with Black Horse Finance, so I agreed they could email me further details. What they sent was a permission to proceed form with terms & conditions. I read them & interpreted that I had nothing to lose if I signed the form as they would send the 'regress' to me by Cheque, then I would settle their fee within 7 days. They have now rang to reiterate, their standard form covered a variety of circumstances and that in my case, because they have already done their work, my 'regress' lies in an 'ESCROW' account & my payment of their fee is required in order for them to release it.. So I have told them I am not prepared to do that without doing further investigations & I have pointed out that there is a 14 day cooling off period - so they are calling me back later this week. They do seem keen for me to check things out so have emailled me their CRM registration & company number - both of which check out fine.

As I write this I can feel myself flushing with embarrassment - however, I have seen other threads in this forum suggesting First Plus Claims Ltd are legitimate. I've been scouring the web for known scams, & this one - if true, seems a new one as their upfront fee is not the common scam to begin a claim process. They say the regress would be paid by bank transfer on the same day as I pay their fee.

As I'm not keen to part with any money up front, I was wondering if there is anything legal that backs up their assertion that their fee terms are legitimate due to the county court involvement, I've rang a local solicitor, but they want to charge £300 for advice, Citizens Advice referred me to my local office - where I am continually on hold, and anti-fraud bodies only seem to be interested if I become a fully fledged scam victim.

I've not parted with any money or bank details, the only thing they have on me is my signature & address on their form on which clearly has the 14 day cooling off period. Which now the mists of greed are subsiding - I am inclined to invoke.

I'm not expecting legal advice here, but I would really appreciate any opinions or stories of similar experiences.

Thank you in advance.