Based on a similar experience, unfortunately 1st credit will go all the way with this, they have put a charge on my property and are currently enforcing it - meaning they are trying to sell my house. Neither my husband or myself are self employed but a family member who has a similar size debt with 1 st credit and who is self employed was issued with a statuory demand by 1st credit - he was then given 21 days to come up with approx. £12k and couldn't - so 1st credit proceeded and made him bankrupt.
I know people try to be helpful on these forums but be careful of what information you follow thru with as unfortunately it did not help us, I know we got into debt and I was not trying to hide from it and wanted to accept responsibilty and pay and therefore I acknowledged that the debt was mine, after all it delays the invitable by denying the debt - they do have signed agreements and unfortunately also used the recorded conversation in court as proof and acknowledgement of the debt.
Good luck - try and come to some arrangement with them would be my advice.