Have you ever heard of a deferred second mortgage?

Hi,

I currently have an outstanding debt that is being settled through the courts.

At present my debtors have a lien secured against their house and going forwards it was intended to continue to have a lien against the house while they repaid their debt.

They have come back in the latest round of contract negotiations wanting a "deferred second mortgage" instead of the lien. I have never heard of such a thing and I'm concerned about my level of security in the event that I agree to this. I understand their reasoning for wanting this, as the lien prevents them from remortgaging to extract more equity from the property in order to pay back their debts. However, my lawyer has not yet fully informed me of the implications of this and I am trying to do some independent research, so that I feel more informed.

Has anyone heard of such a thing before?
Does anyone know what security implications this has for me and getting my money back?
Do they have the option to refinance, even with the lien, if I give my consent to do so?

Thanks!