Negotiations can only really start once the lender has justified their claim to you. In most cases, the shortfall sums being claimed are ridculously high and completely unjustified because the lender has sold the repossessed property for many thousands less than it was worth.(posted 8518 days ago)There is no point in you making an initial offer until you have forced the lender to justify their claim. Otherwise you will be paying the lender money they are not entitled to.
Only when you are satisfied that amount being claimed is justified, then you can start to negotiate paying in installments or maybe get it reduced even further by paying a small sum in full and final settlement.